I recently got the largest Superband.
http://www.performbetter.com/detail....tegoryID_E_352

I did squats with it for the first time today. It provides around 100 pounds
of resistance. Maybe a little more.

My first one was the next size down. I cut it so I could use it as a regular exercise band. Squats, deadlifts, etc. I have a high back chair and I can wrap it around the back of that and use it as a sort of bench press. Great for shrugs.

But the big guy is a whole other animal. Good bang for the buck. I don't
feel you should only use bands, mixing it up is a big part of weight training. But there are a number of things I like about these bands.

You can let go without consequence. Moving your hand position up or down the band causes big changes in resistance. And the one band can
be used for several different exercises, while not taking up space or costing a bunch of money. Think of it as a Bowflex for 50 bucks.