Yeah, I have one of the first Bissell Lift Offs, it's a neat vacuum but I don't really get the purpose of the lift off.
For above floor cleaning, I really don't like using most of the tool on board uprights. To me there's no way they could be as good as a canister for that purpose, unless they have a very long hose and you can just leave them in one place while you clean. Which most you see of the big-box ones do not. But they do have stretchy hoses that make them topple as soon as you touch the attachment to the surface to clean. I've had them topple ON ME more than once and it hurt!
I still don't see why people love tools on board uprights so much and say they're better than canisters for above floor cleaning. I don't see how that could be true, unless again, you're using it like a central vac. And you could do that with a canister just as well.
So the only thing I see about these lift off machines is that they figure since everyone these days wants an upright, evidenced by their near total domination in the big box stores, then making one that's a bit more convenient for above floor cleaning, without being a canister, might be a good sell.
Now I think there are some lift off machines that convert to canisters with wheels, if I remember correctly. I might be wrong, but I thought Shark had one.