I initially had an issue paring the device. After deleting and reinstalling the app, and after adding a transaction (transferred BTC to my BlockChain account using a web browser), and after quitting and relaunching the app, it finally paired with my account. I'm not sure what really made the difference.
But now, when I launch the app, there's a very quick loading screen, then I'm stuck on a page showing 1 transaction (8 confirmations). The 2 apparent buttons at the top corners, and the 4 buttons at the bottom don't do anything (the left piggy bank button appears to be for the screen I'm stuck on). It's almost like a static screen shot, in that nothing I do give any feedback, or changes the screen. Hard reset doesn't help.
I again tried deleting the app and repairing again, and again getting stuck on pairing (quitting the app and restarting it seemed to get me paired), but I'm still stuck in the same screen (but showing more confirmations). Note that it seems each time I quit the app, then relaunch it, the app crashes at first relaunch, then loads the second time. I'm using an AT&T iPhone 4S with 32GB memory (1.1GB free) and the current iOS (6.1.3). I'd love to use this app, but it seems I've tried everything I can think of... Please let me know if you have a clue what I can try, or if there's any other info I can furnish.