I am a big fan of dabbling with the aftermarket parts because I kind of find it fun...that being said there are so many lackluster things that have been released for the SKS...it is a crap shoot buying anything. Even the new and improved NC Star gas tube assembly is using recycled crooked tubes from their previous release. The variances from SKS to SKS also don't lend to 'every' product being universal....so buying fitted used parts proves to be frustrating.
Oft, I just try to restore...but I do have my bubba needs too. Recently we have been offered the Archangel stock...which I like, but is overpriced IMO. There is also the Kicklite stock...which looks OK, but basically just is an upgraded Tapco concept. There is that new Leapers mount, that is an oversized, overpriced version of the same ol receiver cover mount...and the aforementioned new NC Star tube. Everything else seems to be from Canada...whose recent influx of cheap SKS's would seem to lend to their own aftermarket bloom. While I respect the two competing companies making those new scope mounts...they also seem overpriced and invasive.
As for the American market, I think we have seen the heyday of aftermarket and will now have to deal with NOS scores. Some of which are very cool designs...but most of which are outdated and never were practical in the first place. I do think the recent influx of war horse SKS's has given many people pause as they don't give the same cheapo nature that barrels full of 'new' Chinese $79 SKS's once did. I like to think this lends a bit more 'street cred' to the SKS than it usually gets...original parts sure are getting a lot more attention than they used to.