My uncle has that one. I have not used it, but he says it works pretty well. I have an old Gravely that has the factory grass vacuum on it. It works pretty well, but I figure one of those would work much better since the box on them is made more to vacuum instead of just throw the debris like mine.
If your lawn is fairly flat one of these will work very well and fast to get up leaves and grass clippings. You can ride around till the thing is full, stop where you want to dump the leaves and drop the load w/o leaving the seat of the mower. I had one for a few years but my yard has to many gullies and uneven ground around many big tree trunks.It will also sweep up small sticks and branches w the leaves.