Vacuum Cleaners Discussions

Ive have been researching vacuums the past couple weeks or so. I came across this AMA (Reddit) where the gentleman REALLY suggested Miele canisters for carpet AND bare floor. The apartment I live in now has mostly carpets, but eventually I will be moving into a house. I like carpet, but my girlfriend likes hardwood flooring more. You can probably guess what our next house will have :(. So, I need something that is great on carpets and barefloors (our lease isnt up for 16mo, and just in case the next house does have more carpet than wood flooring.) Two weeks ago, I was absolutely set on some sort of Miele S8 (I was sure I needed the 12 billion step filtration system). Last week I was set on the Sebo D4 (Better warranty, cheaper consumables). Now I am looking at the Riccar Brilliance models. I saw that they have two motors in them; one for floors and one for tools, basically. Since the Riccar doesnt need to compromise suction powered between tools and floors (Bypass vs Direct), wouldnt it be possible to hook a turbo brush up to to hose and just use it as a canister (getting under furniture, cleaning couches, vacuuming hardwood, etc)? I saw some youtube videos of the Riccar vs a Dyson. It highlighted how much agitation the Riccar had vs how little the Dyson has. Ive been reading, and the general consensus is that Agitation + Air flow = cleanest carpets. I have yet to see a video that shows any canister that shakes the floor as much as the Riccar.