I just purchased an M Sport and it's very good and bad.
Good: Looks,feel ( although small ), accuracy, ease of use.
Bad: Cheaply built, jams, comes with one mag and extras are $75!, likes specific ammo.
I used CCI MM's and Stingers, both worked about the same. I didn't get through more than 2 mags in a row without a jam or the slide not going all the way forward after a shot. I already polished the feed ramp and next I'm going to fix the entry of the chamber because it's not even perfectly round !! I can't believe Sig would even put their name on these things. I knew about the problems but bought it thinking I could fix most of them. It's more for showing first timers how to handle and shoot a pistol before I hand them any of my good stuff.