-Magpul MOE mags: fine for hunting and target, but wouldn't trust my life with them since there's no metal reinforcement
-Magpul M3 steel reinforced mags: very nice and fitment seems better than steel in some AKs, maybe not all - but then again steel doesn't fit all well either. A little pricey...
-Commercial steel AK mags (Bulgarian, Polish, Croatian): these are hit and miss. Some fit great, but about 10-20% have fitment issues. This is my experience only and yours may be different. Best bet is to buy them from reputable seller that will allow returns on those with issues.
-Combloc steel mags: tough as hell, generally fit good with a little wobble but who cares. Price is hard to beat. If you're lucky enough to find them new or in excellent condition, these are the best bang for the buck.
-Refurbished Combloc mags: I've seen them from various origins and my experience has been a bad one so I avoid them at all cost because you never know what you are going to get. Rust, thick or poor paint, grind marks, dents, etc.... and who knows what condition the springs are in.