I have one CZ 452 (American) and three Marlin 39's (39A, 39A Mountie & 39TDS).
For accuracy I have to give the edge to the CZ. see picture: http://www.grovestreet.com/jsp/onepic.jsp?id=1168549
The CZ is a good quality rifle and I would rate mine equal quality to the Marlin 39 and much better than any Marlin bolt I've seen. The CZ has a good trigger and is easily made better with Brookies trigger kit.
However,,,,, If I HAD to pick one or the other, I'd pick the 39A Mountie because it's my favorite hunting rimfire. The accuracy is very good, see picture of 5 in a nickle at; http://www.grovestreet.com/jsp/onepic.jsp?id=1114275
That was an unscoped group so I'm sure a I could tighten it up a little. One hole? maybe. The Marlin is less finicky about ammo too.