There's no legislation yet on bitcoin apps. I mean you can look at them as "banking apps" and anything banking is regulated, which is why they're safe.

But anyone can just throw a Bitcoin Wallet PANDA PARTY! on Google Play and you're free to use it. There are no laws, nothing. That wallet could very well be giving u pre-made private and public keys....

So yeah, it's wild wild west.

I would just trust apps that people say are trusted.