The Tokarev was the earlier design. It is a knock-off of the John Browning delayed blowback design but with an integral trigger and hammer group. The correct ammunition for the Tokarev is a .308 diameter, 85-88 gn ball at 1390-1400'/sec from that barrel.
The CZ-52 is a later design that uses a roller system to aid in functioning and recoil (to allow the pistol to use hotter ammunition). This pistol is larger and heavier than the Tokarev. This pistol will allow the use of submachine gun ammo as it has a better recoil system. Some of that submachine gun ammo is even too hot for the CZ and there are more than just a few instances of folks having their psitols come apart on them using bad ammo, so caution is well advised.
For a comparison of different load levels of 7.62x25mm ammo you should visit Ron Reed's site. Ron is one of our sponsors and produces about 13 different loadings in that caliber.
It has also been said that of the Tokarev pistols, those produced by the Polish are the best - the safety seems to be functional (both location and function), and the fit and finish are better than the Chinese or Russian made pistols.
You can also get more aftermarket parts for the CZ than the Tok, grips and finishes. The CZ is a bit bulkier but is supposed to shoot very well. HTH. Mikey.
