I have two 75Bs... one 9mm and one 40sw.
They are great shooters; I did some polishing of the triggers, and put in lighter hammer springs that made the pull very nice. They were a tad gritty and heavy when new. (I used 18lb springs for reliability without the need for changing other components, it is an easy swap, and low cost from Wolff)
The triggers are known to smooth out with use... I have never felt a "bad" original 75B trigger, but some do have a little gritty/notchy feel at first. Once the parts wear into each other, things smooth out. The positive sear engagement can give the triggers a little creep, but nothing like some striker pistols have.
There are plenty of aftermarket parts available for the original trigger, should you feel the need. There may be Omega parts as well, but I have not had the need to look for them personally.
CZs come in a safety or decocker version. The safety can be cocked and locked, or manually lowered for DA carry... the safety will not engage when the hammer is not cocked. (the Omega trigger may differ here, I have no personal extended experience outside a store with one)
The Omega trigger is a simplified system, and is smoother out of the box as a result. General consensus is that they do not respond to trigger work as well as the original trigger. The original system has dual trigger bars and that may balance out forces helping trigger work shine.
Unless you plan on doing competition and need the best trigger possible, either would serve well.
The Omega trigger allows for switching between a safety and decocker in the P-07/9, and now there is a version of the 75B Omega that allows this as well; though the original version of the 75B Omega did not allow this conversion, so if you want this feature in a 75, make sure you get a newer manufacture. (the manufacture date is on the pistol's slide)
Some different models...
The P-07 and P-09, are polymer framed. The P-07 is G19 sized, and the P-09 is full sized and holds 19+1 in 9mm. They have the Omega triggers.
The P-07 has a gen II version (it has the angular hammer of the P-09, rather than the original rounded version, for easy identification in the store) Basically they refined the design a bit and made some improvements with the p-09 that made their way to the P-07. One of the most popular changes is the flatter trigger, rather than the sharply curved original.
The SP-01 is a 75B with an extended dust cover/rail. The added mass of the extended dust cover of the SP-01 reduces muzzle rise a bit over the 75B.
I really like the rubber grips that comes with the SP-01 over the basic plastic versions that many models have. They were a cheap upgrade to my standard 75B, at less than $20, and worth it to me. Some like the thinner aluminum grips that come on the fancier models.
There are the compact versions as well, steel or aluminum framed.
The P-01 is a variant of the 75 compact, with an aluminum frame and extended dust cover. (the P-06 is the 40sw version)
There are variations of the 75B and SP-01, that mostly come down to setup. The 85 for example has an ambi safety.
Then there are some variants, like the Shadow line, that start to tweak the pistol to improve performance, like the trigger, but that starts to add to the cost.
The CZ-97 is a 45acp version, it is physically larger as a result. I owned a clone copy of this pistol, and found it a nice shooter, though a bit large for my hand.
Any specific questions... ask.