Seriously, the chap above had a point. The Halo/Reloaders are nice but I've seen too many break down or have issues. I've been runnning a Vlocity for 2 tournaments now and it's been utterly excellent, except when I over filled it and it jammed, but that was my fault over the hopper.
They might not be quite as squat but don't go above the line of your head to it's not a worry. They are fast, reliable and a bit cheaper than Halo/Reloaders. I'd not part with mine now.