Heres my take on it:
I had a CZ-75b in the polycoat and never had a single stoppage with it. The trigger wasn't great out of the box, but did get noticeably better over the first 500 rds or so. Felt very similiar to a HP in the hand and would group with pretty much anything in the service pistol class. Sold it because I can be a very stupid person. Readily available full cap magazines make this a better buy now.
The Sig will probably be very reliable, heavy, have a good da/sa trigger, kind of hard to work on, very accurate and the priciest. M229 is the most accurate .40 I've shot and has had only one ftf in 3k rounds.
I've had a good bit of experience with glocks. The trigger takes some getting used to, but you can get used to it. The grip on the other hand is harder for me to get used to. I've had 4 or 5 of these the most accurate was a G30 and the least was the G23, but even that one wasn't too bad. I know that every manufacturer has its ups and downs and I have seen broken Glocks, but I have never personally had any kind of stoppage with any of my glocks. That is a big deal to me. I currently only own 9mm variants, and they are not my favorite pistols, but they have a terrible tendency of never letting me down at the range. They are easy to maintain and work on if the need arises, and factory parts are everywhere. I would imagine the G34 will be more accurate than most of us. You may want to pick up a used G17, they can be had for less of a layout than the G34 and they are pretty easy to get rid of if you decide glocks are not for you.