In the past I would never have considered using these "pussy rubber bands ; free weight wanna bes " . Now I think differently
They complement free weight and other resistance training quite nicely .http://www.bodylastics.com/
Terrel Owens uses them as a primary source of resistance
Many bodybuilders even put these bands or chains on the ends of barbells as they train . The reason for this is, take bench press for example. It's hardest to lift at the bottom but close to lock out at the top it's easier . With bands it's the opposite, the farther you stretch them the more resistance they supply , thus putting them on free weights provides more even resistance. Chains do the same when added to barbells, the higher you lift the bar, the more links come off the ground and provide extra poundage the higher you go.
These bands are great as a stand alone system though and can mimic hundreds of gym machines and exercises unique to themselves and has clip on hand handles as well as ankle raps for the legs. The company has a daily workout show live with the system and blogs the episodes to be watched for free. Currently nearly 400 episodes are blogged. The set I purchased provides anywhere from 5 up to 388 pounds of resistance. Around half the exercises you use your own body to anchor them, the other half you use a door with the included door stop. I recommend getting the optional anywhere anchor that lets you use the system with telephone poles, trees, a fence, any pole, etc.
Also a fan of Lineline's power pushup 3 which makes regular pushups even harder .