I get that question very often; “Which time tracking app would you recommend?”. And my answer is always the same: “I never used any, just look at my The ultimate guide for doing things with Asana and decide for your self”. That shitty answer stops today! Let’s build a comparison of those app together 
I’ll consolidate all the comments you post to improve the below list. The list below is alpha-sorted.
Thanks to the initial thread Which Time Tracking App works best with Asana? but I believe such a detailed comparison will be easier to use.
Edit January 2023: Asana now has a built-in time tracking!
Clockify
(help us complete benefits & shortcomings)
Chloe One of the benefits is that you can record time directly in a task, there is a timer. But you have to manually create all the projects in Clockify, there is no sync between project list in Asana and project list in Clockify. And the reports are in Clockify. 
Dan Worden
Benefits:
For our organization, the cost is going to be one of the top ‘Pros’ for Clockify (but that may vary for your needs). I thought it was interesting to be able to track time based on practically anything, (even by highlighting a section of text on a website) and thus it doesn’t have the same issue when tracking time with Tasks that are only in My Tasks. The Clockify phone app has the ability to store data locally and force ‘offline mode’, so you can track time on tasks when you don’t have a wifi or cellular connection (useful for if you are working on long flights like I do, or in remote areas where a stable connection is not always available. Note EverHours app needs an internet connection to load).
Cons:
The whole experience felt a bit more clunky, the UI is more like a mid-2000s table, and (especially with the Chrome extension) it would take a few seconds for the clock to start showing that time was tracking. Clockify does not automatically recognize projects in Asana so you do need to go into the settings and toggle a switch, but once you do that it actually works quite well, (Just an extra step that we would have to walk all of our staff through when setting it up, which is not always easy as many of them are remote, and not all are super tech-savvy.) but it will not automatically refresh or pull new data from Asana, meaning if you change a project name or task name in Asana it will register it as a new entry rather than recognizing and associating it with the prior work on that task/project.
DueFocus
(help us complete benefits & shortcomings, and gather testimonials)
Benefits: Good Asana integration, mobile app, good and flexible reporting system, easy to add, delete, edit data
Shortcomings: it is not “native” Asana integration so it requires browser extension and setup integration between both tools.
Bigs: I use Everhour and I love it. […] The integration into Asana is excellent
David Jané A good time tracking tool which powers go beyond Asana integration. Good reporting and nice add-ons that will help your team by having all Asana projects tracked and monitored.
Dan Worden
Benefits:
Better UI and UX. It felt like an overall more polished product across all 3 ways of tracking time (website, extension, and app). I didn’t notice any lag when starting and stopping the timer on web or with the browser extension (slight lag with the app), and the integration with Asana and its project structure was automatic (didn’t require any extra setup) and worked very well.
Cons:
The biggest issue I ran into is that you cannot track time of a task that solely exists in the My Tasks section of Asana (This is because EverHour integrates with Asana Projects to organize your time, and in Asana, tasks that are only in My Tasks are actually not associated with a project.) EverHour rounds time to the nearest minute every time you start and stop (you could argue this as a pro or con, and I realize this is super nit-picky, but for my analysis im considering it as slightly less accurate). Finally, the cost of EverHour is more for our organizations needs. (Keep in mind, that was just for us at this time, and the pricing structure may change at a later date.)
Benefits: natively integrates with Asana
(help us complete shortcomings)
Ryan_Carpenter: I have been pretty happy with the Harvest integration.
Mark Nattress: I’ve been using Harvest time tracking and its integration with Asana for some time. Its easy to use and extract reports that provide some insight on where your time goes. It’s a paid subscription, but well worth it… With Harvest I’m able to pull all my ACCURATE time on work and copy / paste it to the company “standard”.
Hourstack
(help us complete benefits & shortcomings, and gather testimonials)
Hubstaff
(help us complete benefits & shortcomings, and gather testimonials)
Ryan_Carpenter: Hubstaff synchronizes right away and integration of Asana tasks into Hubstaff has worked consistently for me over about four years of use.
Andrea_Mayer: * we are using Hubstaff since quite some time already […] It connects very well with Asana […] This is a very good tool to measure efficiency […] we are quite impressed as it has so many features + they are constantly adding more and whenever you share feedback they are really active to try and implement Full comment
Benefits: easy to use browser plugin, invoices for customers
Shortcomings: documentation mostly in German
Florian_Keck: We’re working as an agency an are using mocoapp.com developed by Swiss based company. It’s a full featured agency software with an extra browser plugin that let’s you easily track time from tasks to budgets. You can craft offer sheets, invoices, spendings and so on. You’ve got a your clients contacts in one place and its so very slim and easy-to-use. Best we’ve had so far. Moco does the backoffice, Asana the projects
Officetime
Benefits: simple, no subscription, integrates with Asana, powerful reporting, easy-to-use, Asana tags are automatically assigned to time entries
(help us complete shortcomings)
Martine_Warburton: really simple, but works well and its a one off fee no subscription
Outplanr
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PomoDone
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ProfitTable
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Tick
(help us complete benefits & shortcomings, and gather testimonials)
Benefits/Shortcomings: (help us complete this section)
Heather_Dube: Do not use TimeCamp. Stay far away. Their product is constantly not working properly, their integration is really poor.
Christoph: I agree that TimeCamp has reliability issues. It just happens sometimes that the numbers don’t add up.
Time Doctor
Benefits/Shortcomings: (help us complete this section)
Ryan_Carpenter: I gave up on Time Doctor, because the synchronization took too long in the use case of adding a task in Asana and then immediately starting a timer in TimeDoctor. This has improved since TimeDoctor updated its UI some months ago. […] With that said, I have to disagree when it comes to their integration. Last time I checked, the TimeCamp integration was the only one able to fully and flexibly mirror my Asana task hierarchy and track time against every single sub-task, sub-sub-sub-…task.
Timely
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Timeneye
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Benefits/Shortcomings: (help us complete this section)
Marie_Malikova: I’ve been using it for several years and I really love this app. It integrates with Asana and you can track time spent on tasks from Asana board. Besides, you can get detailed time reports.
Marina: I’m working with TMetric 4. Very native integration with Asana. And what’s most useful are the features payrolling and budgeting. Makes it very easy to work
Benefits: integrates well with Asana, simple, projects & users sync
Shortcomings: a few glitches on sync (always solved quickly)
josh.hester: I have used it for years and really like its streamlined design and simplicity. […] it interfaces very well with Asana
Kim Caloca: I use Toggl and it’s become a great solution for tracking my time spent on tasks from other Asana workspaces. I set up Zapier automation so that starting a timer in Toggl (from an Asana workspace that’s not my own) creates a task in Asana for me and marks it complete when I stop the timer. This helps me keep some sanity by being able to see how many tasks I’ve worked on throughout the day more easily. I also set up a zap that pushes my completed tasks into Exist.io (which also integrates with Toggl and Rescuetime) so I can look at correlations with my productivity. Super nerdy and very satisfying.
Diego Jiménez Vallardes: I just wanted to share my own experience with the time-tracking tool, Toggl. For me, it’s the best time-tracking available. Aside from its life-time free version, which I use, its simplicity and the easy way it is to write a new time entry is what makes this app the best. Its integration with Asana makes life a whole lot easier since you can begin a new time entry with a press of a button so you can concentrate on the important things. The name of the entry is determined by the name of your task, and the time stops running once you stop the timer either in Asana or in Toggl’s main page.
Benefits/Shortcomings: (help us complete this section)
GSH: I just tested it and found it very clear and rather well usable with Asana.
TSheets
(help us complete benefits & shortcomings, and gather testimonials)
Benefits: integrates with Asana
(help us complete shortcomings)
Monika: we are working now with zistemo which is really fully integrated into Asana including Budget per tasks and extended time management functionality without switching between Apps.
Dan: I have tried a few integrations and ended up using zistemo to track my time in Asana. Can recommend, great tool.
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