MZ (Motorrad- und Zweiradwerk GmbH) is a German-produced bike, though the factory on which it was built, originally was started by a somewhat famous danish inventer named: Jorgen Skafte Rasmussen.
See wiki-link below for more detailed history.
http://en.wikipedia.org/wiki/MZ_Motorrad-_und_Zweiradwerk
The CZ (Česká zbrojovka) is a Czechoslovakian motorcycle brand, is, and has always been, considered as a worse bike then the MZ, not that any of them were anything special. They both were cheap, badly manufactured bikes, however the price made them interresting for some people.
Wiki-link below.
http://en.wikipedia.org/wiki/Česká_zbrojovka_Strakonice
Lastly, someone mentioned something about russian bikes in general were of poor quality, compared to the CZ !
That might very well be true, but acturely, motorcycle enthusiasts considder the MZ to be a way better bike than the CZ.
But, Walter Keller from Florida, USA, mentioned the Russian Ural-bikes in #12 on page 1 in this thread.
The Ural-bike is produced in Russia yes, and it may be, that russian bikes in general are crap, however the Ural-bike is acturally an old BMW-construction, stolen by the soviets, during WW2.
The Soviet Defence Ministry simply bought 5 brand new bikes, then let russian engineers dismantle theese bikes and do reversed engineering on them.
They acturaly got away with that pretty good, cause the Ural has a reputation for being reliable, strong, and easy to fix in case of mechanical trouble.
In western-europe, Ural-bikes are hard to come by, and even their age, and simple, somewhat uncomfortable construction taken in to consideration, theyre greatly apreciated, and respected amongst motorcycle-enthusiasts, also the Ural-bikes are quite expensive !
Especially the ones with sidecar, were the sidecars wheel is coupled to the bikes rear-wheel in order for the sidecar to pull, as well as the bike itself, is considdered an interesting and valuable model.