My experience w/the SKS...
is that the quality and accuracy of the individual weapon varies widely. You can't generalize.
Have never handled a Russian, however "everybody says" that they are the top of the line. Have owned a Romanian which was in superb condition (looked almost new, except for the Cosmoline) which shot like used oats from a horse. Sold it. Briefly owned another Romanian which had a bent bbl, would you believe--got rid of that one really quick! That one must have been out of the first crate in an importer's shipment, so they used it to open all the other crates.
Now have a Yugo which doesn't shoot much better. Again, it is in pretty good shape, ding, scrape, and dent-wise. And it's true, the Yugo is built like a brick pizzaria. IMHO you'll never find a more rugged, reliable semi-auto rifle.
BTW, someone in one of these posts said they had a machined-receiver SKS--What would be unusual would be to find one that isn't machined. They all were, even the cheapest of the Chinese ones (which were built on Russian equipment the Russkies sold to China after Russia replaced the SKS with the AK. There are even "transition" SKS's, of interest to collectors, with Russian markings on some of the parts, which came with the machinery, and Chinese markings on some of the parts which the Chinese made.)
Have talked with friends who say that the Norincos are varying in quality--some are great for accuracy, some aren't any better than a slingshot.