I purchased one of their 7.62x39 side charger uppers w/ BCG, back in May when it went on sale for $199.  I had an extra Aero lower laying around, so for the price, what did I have to lose on a side-charger?
 I really didn't have high expectations due to issues that I remember from BCA in past years.  I've now ran 400 rds through and it's been flawless. I would like to add that I've been firing Tula steel and haven't had any issues with light strikes, feeding, nor extractions.

Per recommendations on the forum, I installed a Black Rifle Arms enhanced firing pin and a Wolff extra-power hammer spring. Comparing the firing pin that came with the upper, and the BRA one, they are the same length, but the BRA has a better finish.  

Accuracy has been 2.5 MOA when I slapped on my Trijicon Accupoint, (I plan to just keep irons on it) again with Tula ammo.
The finish on the upper, BCG, and barrel is very clean/nice and on par with my high-end rifles.
Overall, I'm pretty damn pleased with the upper and I wouldn't hesitate to recommend one to a friend for a fun blaster, especially on sale for $199.
(not a shill)

It sounds like you put it on a standard lower -- what mags does it use?

Correct, just a good Ol' Aero standard lower.
The mags, again recommend here, are the C-Product Defense (made in the USA) 30 rounders. I load 29, just too tight with 30.
I wish I would have picked up (2) 20 round and (2) 30's instead of purchasing (4) 30s'