I also have the regular m22's as well as some onwalls. The onwalls sound very good when a sub helps pick up the lower end. The In-walls have a little bigger internal cabinet, so I'm guessing they might be a bit better in the bass area, but the onwalls are much easier installation.

For that room I would go with a bookshelf or floorstanding speaker, if it was me.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85