Had one and sold it. Touched briefly on it in a different thread but I'll go into more detail here.
I've had 5 CZ rimfires of various types and have sold off every one of them. Way over rated IMHO.
The 455 American I had was also very ammo finicky. IIRC the only standard grade ammo it shot well was Aguila SV. Anything else group size about doubled. And my standards are not that picky for that matter. Also the extractors needed some work before they would extract loaded rounds, even then it never was 100%. That seems to actually be a fairly common problem, also had a 452 with the same problem tho not quite as bad.
Also I post on a rimfire specific forum and it seems like a high percentage of the CZs that are good shooters have had some work done to them, anything from a simple trigger job to barrel replacement. For the kind of coin a CZ costs, that shouldn't be necessary. I've heard some real horror stories on the 455 series also, really poor internal machining, uneven crowns, rough chambers, lousy rifling.
I will say all the ones I had looked good and a couple had some really nice wood on them, but for me functionality takes precedence over form. I don't care how nice the bluing is if I have to pry a loaded round out of the chamber with a pocket knife.
I own 2 of them...one in .22 and one .17. The .22 is really accurate and I'm very happy with it. The .17 is good, but not as accurate as I've heard on forums so I'm a little disappointed. Going to pillar bed i and see if things improve.