Glocks are fantastic shooters. Most accurate shooters? No, but more than acceptable for what you want to use it for. M&P's have adjustable backstraps, good for various hands.
9mm is good to start. As a new shooter, there will be less recoil, and it will be cheaper to shoot.
Some people have had problems with the Gen4's--new design can lead to problems but most of them have been worked out by now. As for feeding and reliability problems, it should be good.
Have shot the Gen 3's and Gen 4's. The Gen 4's, with the dual recoil spring feels like it has a little less recoil.
Never shot a CZ, so I cannot compare. Shot the M&P, nice gun, just partial to the Glock. Yes, I have drank the Kool-Aid.
If you do find one, see if you can stay away from the adjustable sights. This is personal, I know some on here like them, but I get a better sight picture with the standard glock sights. Glock night sights are good, if you could find a set of Warren tactical sights even better.
Get the gun. Shoot it. Shoot it a lot. Enjoy it. Shoot a friends gun that is not a Glock. You might like it better. You might not. Worse thing that can happen is you sell it to get another gun. Shoot it. Shoot it a lot. Enjoy it. Get my drift?