Ubertesters is a well made platform for mobile app testing either by in-house testers or crowdsourcing.
It is easy to use, for both the product testing manager and the testers.
As a manager, you get a clear overview, via the web dashboard, or all the projects currently being tested and you can drill down and see all the issues per built of a specific product.
The manager gets a detailed report of all bugs reported with crash report, tester's details including their phone type and OS version and the description (with screenshot if taken) by the tester.
A tester has to install the ubertesters app on his phone which is used to install the tested apps, it adds an icon on each tested app from which the tester can report bugs, take screen shots, draw on the screen to mark areas and more.
The ability to have testers from other counties helps for Multilanguage and region testing if useful for the beta testing phase, something not easily done in-house.
It works on ios and android, which is an advantage.
I think this is a very useful and easy to use solution for beta testing your mobile app.
Not too much to dislike about ubertesters. Crowdsourcing testers may vary in quality and new testers will take some extra time to learn the app being tested.
There is little extra work needed to add the needed libraries to your project.
but, I find all those to be minor issues.
All in one platform for testing and managing the test cycle (it integrated with other bug tracking systems)
Useful for beta testing phase.