I use both and like both, but overall I prefer Breez over Phoenix. Breez has some added features like NFC support, a point of sale interface, and in-app integrations with other lightning apps/services/podcasting 2.0. It does a better job than Phoenix of warning you when you create an invoice if it’s going to require a new channel to be opened, and there’s a command-line-esque dev mode where you can issue commands to the node and see other advanced information about the node and channels if needed. Phoenix does a better job of displaying your existing channels and liquidity. I’m also using them on iOS, and I know the Android version of Phoenix has some additional settings that iOS doesn’t, so that might make a difference.