Just to help you age the machine we bought one of those from Shark on 1/1/17. It's been great. We got it as a package on their website and I later ordered a second filter set so I can just have one set washed and clean ready to go.
I could be wrong but pretty sure the one on the right is older (by model year anyway) than the left one and one on the right thats a curb find is the original powered lift away Only say this cause dont remember seeing one like the one on the left till few years well after the original power lift away came out but could be wrong and or these just happened to he made at different times individually as they kept the original power lift away on the shelves for long time atleast here in akron/canton area of ohio lol
the NV750 is the rotator truepet and the other one that thomas gave you is a similar called the navigator powered lift away from the target store and the rotator has handle controls and the suction is on the handle when switch to hard floors and turns the power brush off and the NV585 power button is similar like your green rotator powered lift away speed so the NV750 has handle controls like other sharks like the apex vertex and strados even shark still makes new designs of a navigator and the rotator models and at bed bath and beyond has the rotator powered lift away with a (zero-m) self cleaning brushroll with the handle controls and i have one more thing you should get is a shark Hydro vac mop vacuum compared to the tineco and bissell crosswave you should try the shark Hydro vac but theres a corded and a cordless version you should get the cordless version because the white and blue color and a self cleaning charger and i heard one on the videos in person that it sounds different like the vacuum itself and a soft start powered mop brush so let me know when you get the shark hydrovac cordless XL and see what it can do for you hard floors