I managed to get a hold of a Q-Loader paintball hopper at my local field, and played a few rounds with it. It's an entirely unique product, unlike any other bulk-loading hopper, and has its' ups and downs that you have to get used to, but on the whole it's an awesome product.
The Q-Loader is a magazine-fed, spring-powered offset paint-feeding system. Imagine it something like strapping a skinny hopper to the side of your marker and hooking a hose up to the paint-feed. Each 'magazine' holds 100 paintballs and has a long, carefully-tuned spring to feed the paintballs ridiculously fast (supposedly at 30 balls a second- that's theoretically 1800 balls a minute!). You buy extra magazines and load them before a round begins. It's very easy to slap a new magazine in and trust it'll feed a ball perfectly every time no matter how you shoot.
That said, though, it's... challenging to load and maintain if you don't study the instructions religiously. The first time I tried to load it I pinched a paintball between the inner wall and the spring and the paintball exploded, requiring me to disassemble and wash each piece individually. After a few times, I found out what I was doing wrong and mended my ways, and it gave me no more problems.
If you don't mind re-loading a bit more often (and the potential price tag if you want to buy a lot of extra magazines- 20 bucks each, plus 80 for the starter system), you can't go wrong.