A ton of rifle for the money (almost literally a ton!) I didn't get in at the $499 of a couple of years ago but am very pleased with the one I got for $850 with (3) 40-round Molots.
The bipod could be adjustable but a non-adjustable is also correct IF it's long enough to touch the front of the lower handguard retainer when folded. Apex lists both the Type 1 and Type 2 although they may or may not be in stock when you check. The collar should also have notches that engage corresponding notches in the FSB to prevent full rotation. If the collar can spin freely all the way around it's the wrong collar.
Mine is a runner. The only ammo it didn't like is some ChinaSports SP which, if you're familiar, the cases feel like sandpaper and the exposed lead drags terribly in mags.
I guess it depends on how much you value your Saiga - I do think the AESs will only increase in value but I didn't buy for that reason.
How mine came minus the Chinese drum:
How it is now with CNC Warrior muzzle nut. RPK sling has been ordered and should be en route from Eastern Europe: