I've been working on an iphone app side project. It's been a blast and it's almost done. When I got into this development process I had no idea how hard it was to test an App via Apple's process. You have to send out a giant Zip File and people have to drag and drop the correct files into their iTunes. It sounds kind of simple, but it's really a disaster.
In stepped TestFlight with a very simple remote delivery method for app test builds. Our developer loads the app software into TestFlight, my users authenticate once, and then every build goes to them instantly when completed. It's been terrific and saved me so much time. There are still bugs, for example Hegs can't seem to get authenticated, but overall it's a huge improvement. If you're developing an App, definitely use TestFlight for testing!
P.S. If you'd like to test my new app and have an iphone or ipad, click this link and I'll get you in the cue. Put your name and email in the boxes, TestFlight will send you an authentication email (click that) and you'll get our next Build! Thanks for the support!