Mike, I think the big difference might be the counter rotating brush. When I used my stair tool I scrubed the heck out of the arm rest, when I got the VS I wanted to test it, so I went somewhat fast over the arm rest (the worst area) and it left a streak of white.
I think your right, one should be able to get the same results with a brush and a wet vac, as it is basicaly the same thing. It may also be important to note that I don't have a powerfull stair tool like the stepson.
Micky, I allowed 15 min dwell when I cleaned with the stair tool using orbit natural as the pre spray, after that failed I tried releaseit ds, still not much improvement. So when I used the VS I wasn't expecting it to do much, I was just curious how it would compare.
"i just dont particularly care for the shampoo brush/vac head combo. tends to be cumbersome, and after a while, feels like a ton"
Your not kidding Micky, my forearm is still sore running this is going to be a two handed operation for me.