2 Tippmann 98 Customs, 1 Model 98, Spyder Compact, Tippmann .68 Carbine, Ariakon Overloard, many Wal-Mart nugzzz
Now you can aim!
Only possible thing is that there's no way to adjust elevation.
I'd have gotten the A2 style rear sight with windage and elevation adjustment, but my shop didn't carry the a2 style sight, and this one only cost $35. It's light weight and strong, and aligns correctly with an M16 barrel kit. There's a dual aperature; one peep-hole for ranges under 100 yards, another for ranges farther than 100 yards. But let's face it, the ranged peep-hole is completely useless to a paintball gun. I'm sorry but no one will be popping dudes from ranges of 100+ yards.
And elevation adjustment would be really, really nice because then you could use it to compensate for the arching of paintballs. Even without this feature, it's still usefull to at least 100 feet.
I've grown up shooting rifles, AR-15s included, so I love iron sights. If you're used to using irons sights I'd image that you too would prefer this over a red dot sight. If not, it still helps alot. I'm going to give it a 9/10 because it's very functional, but not a full 10 because it doesn't have an elevation adjustment.