Update
After comparing carefully I I found the Bissell to be better better in some aspects two important to me.
Tank sizes on both was is one gallon. Bissell's looks smaller but holds the same on the clean tank. I think dirty tank on the Hoover holds a liiiittle but more due to its shape but both open up for cleaning.
The build quality on the Bissell which really won me over was much better. I haven't used a classic Steamvac so I can't compare the quality but TTI cheaped out on the entire handle. It's very flimsy/wobbly and the suction door for the hose sounds like the tabs are going to snap off if opened and closed too much. The Bissell has an aluminum top handle and the hole body just feels more solid. The top tank
Back to the tanks the Hoover had locks on both tanks while the Bissell only had one on the dirty tank but the top handle piece will hold it good as long as you dont do anything crazy with it. The Hoover has a separate reservoir for Shampoo which... I'm not sure I have an option on but it let's you rinse with water only. The plug on the bottom of the Hoover's clean tank isn't as good since water drips out from it.
The hose is much easier to connect on the Bissell since the Shampoo hose and suction port on connected on the hose and both just plug in to the machine whereas on the Hoover it separates.
The accessories are on par with each other but the Hoover includes a turbine powered brush which is something the Bissell Bissell dosen't include in box
I didn't have any stains or big mess to do through side by side test (honestly didn't want try to stain the rugs) but they seemed close but the Bissell seems to do a bit better.
The Bissell has an heater for the water and the Hoover only seems to have a "blow dryer" for the flow from what I gather which makes the "Forced Heat" gimmick seem deceptive.
Both have an hard floor attachment which I might try out sometime.
Anyways that was my comparison I guess I think both look nice and preform well but I think the Proheat will hold up better in the long run. But as I said before I never used one but this one but I think the Powerscrub is very different from the original steamvac at least build quality wise.
