High on chain fees cause big fees for lightning transfers, sure to Muun using submarine swaps. Muun was silent for days while this was happening

Muun also uses a non standard recovery method, unlike most other wallets.

These are the main issues with Muun. I'm using Phoenix and it is great. Muun was fine too, but I got burned by some high fees. That won't happen with Phoenix, your funds remain in lightning channels until you decide to swap out to bitcoin.