Everything worked fine until I played multiplayer with my friend on 0.7.1.
After some time spent on his world, MCPE suddenly crashed. Since then, it crashed a lot of times, on random occasions, even when I'm playing singleplayer. The only occasion it is guaranteed to crash is if I destroy a block and try to pick it up (collect it). The crash is always the same: my home screen suddenly appears, not giving any type of crash message or notification (usually if one of my apps crashes, I get a notification, saying that the app is not responding).
The game (especially survival) is unplayable for me now, so I hope this bug gets a fix soon.
Doesn't happen anymore in 0.7.2.