I run the KCI/Asian 20 round mags and they're fine, they run without issue in my WASR, Draco & AK63DS. Tight fit on the lockup lug so a little filing was in order if you want a smooth lockup. But they did work unmodified. Good cheap range mags and about what you'd pay for a Tapco 20.
But nowhere as heavy/well built as my Hungarian Tanker mags, although the current prices are high unless you get lucky on a private sale. IMHO when these were available new/unissued they were the best deal in a steel 20 round mag. Today I'm not sure if any online dealer still has these for sale. If more come in you can be sure they'll be gone in hours.
Arms of America has more of the Romanian 20 round mags back in stock. I've got some coming in this week. They're just battlefield pickup 30s cut down by BadElement, so they're just grade 3 mags but BadElement does good work. But Romys & Hungarians fit best in all mine so for $25/ea I'll try some AOA cutdowns.
And you can cut them down yourself, I cut one of my dented surplus mags down and it runs fine. But it took me most of a Saturday to do it so I'm OK with just ordering them thru AOA and not losing a shooting day in the shop.
I also run tapco & magpul 20s. The tapcos are OK but springs are a bit weaker than the KCI 20s and usually need to be filed to fit as they're wider than most. Magpuls seem to fit everything and feed a bit higher than other mags so they're my first choice for a poly mag.
One other option are the Chinese 5 rounders. yea, just five rounds, but they're cheap, cause, 5 rounds, but they're heavy, well made and every one I've gotten looked brand new. A nice option for the SKS if you want a mag that's about the size of the fixed 10 round mag. And I've seen some cut the legs on the follower down to get a few more rounds in there.