The Yugos are probably a bit better than the commercial Chinese with the pinned barrels (instead of threaded into the receiver), but otherwise, there really isn't much difference.
An SKS will be extremely reliable with the fixed 10-round mag. It will not be reliable with any detachable mag. Most people buy them anyway, because they don't want to believe that, but most usually end up putting the 10-rounder back in. You can load the 10-round mag very quickly with stripper clips.
In order to use detachable mags, you must disassemble the SKS, which is done by pressing the locking button behind the trigger guard. This releases the upper and lower portions from the stock, and allows you to remove the fixed mag.
Also, don't bother trying to scope your SKS. It simply can't be done well, and it will be just another thing sitting in your junk drawer. I recommend either the Williams rear peep sight, or a set of Mojo sights, instead of the rear leaf spring. Either one will be a big improvement from stock.
-Troy