If you shoot mostly non-corrosive, probably the best fit and finished SKS rifles ever made were produced by Yugoslavia. Wherever possible, get an M59 over a 59/66 model as the gas shutoff valve on the 59/66 can be a source of angst unless your cleaning is very meticulous.
The next best, and argueably the most collectible of all the commonly available SKS rifles are the Russianmade pieces. If you get one, try for one with a chromed bore. This will make cleaning easier and also give at least double the barrel life as they wear more slowly.
The Chinese rifles vary GREATLY. I've had real military rifles that aside from the cheap stock wood were every bit as good as a Russian made rifle with all milled parts, etc. and I've had Chinese rifles that were barely fireable they were so poor, with stamped and poorly fitted parts.
If you go Chinese and you are buying in CANADA (doesn't apply to the US as all their SKS rifles have been there for 15-20yrs +), DO NOT BUY A PINNED BARREL SKS IMPORTED BY LEVER ARMS WITHIN THE LAST 3 YEARS!!!
I can't stress this enough. In an effort to pinch pennies the new ownership at Lever re-negotiated with the Chinese to import the cheapest SKS rifles ever. They were allegedly assembled with a mix-match of parts with anomalies such as threaded receivers fitted with sleeved pin-type barrels, etc. These rifles are PROVEN to be UNSAFE in many instances. Sometimes headspace becomes dangerously unsafe within the first few rounds as the barrel shoots loose of the receiver and tries to fly downrange. One owner posted reports that at least one rifle was fitted with a demilled barrel which blew up on first firing.
If I were to buy Chinese again in Canada, I would NOT buy one that had English written ANYWHERE on the receiver as this is a tell-tale sign that it's a recent and possibly unsafe SKS.
All Chinese SKS rifles in the US should be OK if in good condition. Buy with confidence.