It depends on the gun and how well it was fitted at CZ. My 75B had a decent trigger. That's it. It wasn't bad and it wasn't fantastic. I gave it 400 rounds to break in before I made any decisions on trigger. I went all out...SAO conversion, comp hammer, resprung the entire gun, fully polished internals, extended firing pin, removed FPB/lifter, you know...the works!
My byproduct was an absolutely AMAZING trigger pull! It breaks at 2.75 pounds and is 100% reliable with CCI primers. There is no creep, no hammer camming, and positive reset. What more could you ask for?
Well, my wife decided she was getting interested in shooting and wanted a CZ Duo Tone. When her gun arrived, I was blown away. I would say it was 90-95% as good as my worked over trigger out of the box. The hammer didn't have any camming. Zero. None. Nada. For a brand new gun, the trigger was bleep impressive. It was just a little gritty where the FPB lifter starts lifting, but that has disappeared in the first 200 rounds. The slide is still breaking in and it still feels gritty when racking, but the trigger is pretty much good to go. I can't really see myself doing many mods to this gun. It just shoots so nicely as it sits.
Each gun is a thing of its own. Some require more attention than others, and some are good to go out of the box. Remember that these aren't target grade guns...they are combat grade. There is a big difference. Combat grade guns are built around reliability first and foremost. Target guns put reliability to second place in favor of accuracy improvements, such as trigger quality.