I had both, truck loader and the walk behind (I bought the hype!) The truck loader worked really good until 1 stick gets caught, then it plugs real fast and the plug is always in the middle of the tube! The walk behind worked good too, until the bag gets dirty, then it cannot keep the materiel in the back of the bag and gravity takes over, it falls to the front and you will plug the entrance.
I tried the big one on stumps, notta. too heavy. They are good machines and like I said the out fit that I sold them too, still has them. They are great for leaves and saw dust, but that's about it. The one thing that did work good is turning the loader into a blower, flip the hose and you have the biggest lawn blower on the planet! That thing will blow off a yard in a hurry!