I don't even use an app. I just open my browser and make use of Instawallet. Works great so far!

I've downloaded and looked at BitPay, which seems to have potential, but seriously? You can't copy the account's address to the clipboard, or apparently even type/paste an address to send to without first finding a barcode to scan? That oversight is just ridiculous... 90+% of my transactions (for now) are going to be through websites or to other people who aren't generating QR codes. Text addresses, please.

Haven't tried Bitcoin for Android yet. (Haven't needed to trust it, or spend time on the download, since my current method is still working fine.) I'll give it a shot eventually.