I have a blue Autococker with stuff on it. For rec ball/ big games I use a Model 98.
Comfortable. I really liked how it felt. The first strap makes it fit on good, but the two elastic straps make it feel secure. Make sure you get the right size belt, but there is plenty of room for adjustment. The zipper pocket was a selling point for me.
A friend and I bought ours at the Michigan Monster Game, so we got to meet the Mantis guys (who are pretty cool). I thought at the game their customer service was good, so I'd expect the same if you call them up.
I have a 4+3 model, and if all the pods are loaded before putting it on, it can be slightly un comfortable with out proper adjustment. You have to make sure you have it on right. Because the belt isn't separate, you couldn't switch pack size should you ever need to shoot more paint.
It's good. Doesnt this review make you want to buy it?