Nice reg, fairly compact, pretty consistant, keeps me within +/- 8 on co2. havnt tried with air yet but id imagine around +/-5. makes a great foregrip, and keeps liquid co2 out of my mag :)
for the price i cant see why you wouldnt buy it. might be better out there, but you probly wouldnt notice the difference much.
Weaknesses:
not as stylish as most newer regs, is a little small depending on your setup, not a palmer...
Conclusion:
pick up one used, theyre durable as all hell and work great, plus you can get them cheap. nothing really wrong with this one other than its not "the best" but then most of em arent....