I have a 550 American in .270. It seems to be an excellent gun. It shoots into an inch at 100 yards and it is ergonomically very good. The only thing I am not sure of is how well it holds its zero depending on varying conditions. I haven't tried it in a very dry or a very wet environment.
The trigger on mine is the one that can be used as either a normal trigger or as a set trigger. As a varmint shooter, I think you'd like the set trigger. My trigger was a little creepy right out of the box. The manual shows how to adjust the trigger (very easy), and that solved the creep. It is now the best trigger I have ever used. My trigger did get out of adjustment and started creeping again, so I went back in and applied some loc-tite to the adjustment screw.
I've always been a bit mystified about the .308 varmint version of the gun. I think it might be a re-marketing of a sniper rifle. I would personally prefer a .223 or .222 because then I could see the bullet strike because of the lighter recoil.
Would I buy another CZ centerfire? I'd probably go with the new Tikka T3 instead. But there's nothing wrong with the CZ. It's a heck of a deal. I got a good hunting rifle, with scope rings, good cosmetics, great trigger, and good feel, and great accuracy for $500 total.