There have been several threads on this (try Search at the top of the page).
I got mine last November and I love it. I don't have room for a table/frame set up, so it was just right for me. There is so much room, I don't consider it wrestling the quilt under, just repositioning, and since I cant' stand for long periods, this is great for me as I can sit down, hence the name. No tension problems whatever, and I've used different threads, plus different on top compared to bottom and it took them all in it's stride.