The older Zetors with Deutz engines have a reputation around here as being heavy, a bit rough, but simple tough machines, newer ones, idk?
They are relatively rare depending on the area; like everything else a good dealer close by for parts and support is nice.
There are different models in all brands that have had some issues dealing with EPA restrictions and fancy electronics, it's one of the reasons that the market is so strong for used tractors with simple older engineering.
Foto is right, the tractorforum.com is a wealth of info,,,, if you take the "exact" model name of the tractor add it to "tractorforum" & "problems" google should mine you lots of data.
Good luck
Kelly