Testflight Exporter
touchwonders.com
touchwonders.com
The process of adding a tester alone is not intuitive and requires way too many steps.
I switched to installrapp.com for testing iOS stuff because I don't have the time to spend on finding out why the app I released for testing is not showing up in my clients test flight.
I've been using Beta by Crashlytics as it is nice and cross-platform and works with ios7. Downside is the integration process and management console are a little tricky.
On a larger theme, I'm surprised that someone (an enterprising tech person) doesn't set up a service that archives all the data from startups that get acquired and then are shutdown. I'm imagining something like a secure github that has all the channels for each dead/acquired service that you could log into. Or perhaps there could be a company that charged the acquirer a small fee to take over the hosting of just the archived data, so it's still accessible. Perhaps this already exists?