Almost as good as a personal massage therapist!

I got this a couple of Christmas's ago. I have the "no heat" model that lets you select the width of the rollers. It also lets you choose shiatsu or rolling massage, full, upper, or lower back, and spot massage. Heat is a nice addition!
This is a wonderful thing!! Somehow over the years, my back has become very tempermental, and because of that, I've been slowly funding my chiropractor's kids college fund... Until I got this. I still need adjustments every now and then, but this has been a Godsend. It works the knots out and makes me feel like a new woman! I hold my stress in my back and traps and this is so relaxing!
Like the previous reviewer mentioned, set up is a snap, but don't forget to take the little screw out or you'll damage the massager. I originally tried a different model and like some of the reviews of other models, it was too much for my back even with a towel as extra cushioning. Definitely try these out before you buy. Also, remember, this is for muscle knots, not for back pain related to anything else, like disk problems or arthritis. This is the remedy for over use or abuse, not degenerative problems.
The chair is well cushioned and covered with vinyl. It's pretty sturdy, but I always make sure I don't press push against the back rolling part. I just lean back. If you put too much pressure on the rollers, they kind of make a clunking sound. I don't think a very heavy person would have good luck with this massager. I think the roller housing would squish and not roll properly. I usually use the shiatsu mode; I don't find the rolling mode rough enough to work out knots. I love the fact that I can choose to do just my upper or lower back too. It really helps loosen up my knots! Many times this has saved me a long drive and chiropractor bill.
For someone with a tight back or physical job, I think you'd be VERY pleased with this. It really does work the knots out. If I use it before bed, even if it doesn't feel 100% right after, by morning the knot have loosened tremedously and I'm much more comfortable.