great bikes, strong simple engines that go very well. handling is ok but nothing special. i have owned 2 early 90's yz250's and i reckon they are good all round bikes.
the biggest issue is the general age and condition of bikes that are this old, unless you can find a mint example they can be expensive to fix. for example the 92 has a plated bore which can often be worn out and need resleeving or replacement. also aftermarket parts can be a bit thin on the ground for a 92' model. this cost of parts is one of the biggest problems ive found when doing up old bikes as the parts cost more than a late model bikes parts cost. sometimes its better to save up your cash and buy something newer. but if you can find a good one then go for it!
my 2 cents.