I got my concealed permit a few months ago but I've yet to use it b/c I cannot seem to find a great holster for my m&p. Oh yea, i'm a lefty so that always seems to limit my options.
Not a traditional holster in that it only covers the trigger guard, but the Raven Concealment Vanguard 2 is what I use. It's 'meant' for AIWB, but I carry it at about 4'o'clock and don't have any issues. Printing is negligible and it's swappable from right handed to left handed.
The only downside is that if you don't wear an undershirt it does get uncomfortable.
I suggest going with one of the custom makers since you're a lefty. Milt Sparks, Lobo, Mitch Rosen. There are several others, maybe someone will chime in.