If Orange is the new Black, then CZ's are the new 3rd Gens.

I'll keep my 3rd Gens and have a good time with them, but I've now added a CZ 75b Stainless and a CZ Tactical Sport to the mix and have come to highly appreciate them the more I shoot them.
Both feel better in the hand, are rock solid reliable, don't cost an arm and a leg (well, the maybe the CZ-TS), are as accurate as any 9mm you can buy today, and you can buy one just by picking up a phone since they are current production with lots of parts and upgrades available if you like.
My next will be a Compact and there will probably be more after that.

I have never gotten used to the 3rd Gen double-stacks feeling a bit large in the hand, but the CZ's fix that somehow and I feel very comfortable with the two double-stacks that I have.

Don't have an M&P. Never will. For plastic, I go Springfield XD's of various flavors.