One of the worst things Muun does is to charge very large fees to senders. This means that automated services can be unable to send to muun, e.g., exchanges. It can charge over 1000 sats sometimes.

Note that this is quite different than the way Phoenix charges for a new channel. Phoenix charges the recipient. Muun charges a huge fee to the lightning sender, so if the sender has a limit on fees based on normal lightning expectations, it simply won’t go through.

IMHO if you don’t have your own node, Phoenix is the best non-custodial wallet at the moment.