I prefer the 7 round mag. Fits better for pocket carry and I'm used to curling my pinky under the mag.
The 8 rounder will probably be kept in the box for the eventual day that the pistol may get traded, so it has all the original equipment, but all my spare mags will be 7 round.
Yeah, I like the flat, BUT I'd prefer a tiny pinky extension. The extended is too long, but perfect for a backup--assuming i figure out (or someone posts) how they fixed the slippage. I'm thinking a drop of super glue on both sides.
I may end up trading it or taking it off--I'm fine with the bare look IF I'm using a backup mag! ;o)
I like the extended mag for a back-up or for the range, but will carry with the 7 rounder, and got an extra 7 rounder to carry. I like to have at least 4 mags with any of my guns, for rotation etc... Will probably get another 8 round extended mag when they become easier to come by.
When I rented the 9mm Shield, I felt the 7rd mag was just as good as the 8rd when it came to the grip. I've had many guns where I curl my pinky under the grip so I'm pretty used to it. I'll carry the 8rd mag without the sleeve in my left front pocket in a Desantis mag holder as a back-up.