I have both a floating bottom of the line Celebrity (the red on top/brown on bottom) and one with two casters at the front and two wheels at the back (chrome on top/green on bottom).
I opened both to clean them and I noticed there are a few differences as to the fans and the air diffusers.
The floater has a single fan, whereas the one with wheels has twin fans. Both have a black plastic cover with clips that holds it over the fan(s), and there's one round hole on the bottom where the exhaust comes out.
There is foam diffusing material in both. The floater has a yellow foam that looks like a sunburst pattern, a circle with little rays coming out from it.
The one with wheels has a black piece of foam that's round with a hole in the middle. The air comes out through vents in the bottom housing. The floater has an exhaust port on the bottom where you can connect the hose for blowing, the one with wheels doesn't have that.
I think some of the earlier models with wheels do have a blower port that can be closed off when not needed.
With mine the floater is much louder than the wheeled version. That could be though that my wheeler is a QS Quiet Series model. Not sure how that compares to the non-QS non-floaters. But generally vacuums with twin fans are quieter than single fans.
I don't recall if the motors were different between the two, but I think there are slight differences, and I think the amperages are likely higher on the QS one because it's a top of the line model. I know with the power nozzle it's 12 amps like a modern canister would be, but there's no mention of the canister motor's amperage itself.