This is a fantastic guitar support. I've tried many different ones (Gitano, Liikanen, Guitarlift etc...) but this is the best for me so far. Much more comfortable sitting position than a traditional foot rest and you can adjust it to have the guitar sit higher. After starting to use this I've had no back or hip strain from my playing position, which can't be said for a traditional foot rest.
The screw that you adjust angle and height with is easy to tighten and doesn't slip, so you don't have to tense up while practicing, or worry about the support slipping into an unwanted position in the middle of a concert (a problem I've had with other supports). The only downside is that only one side is height adjustable, and for this reason I've considered changing to the Troster model of the same product. Especially if you're tall, have a long back and long arms, the height adjustment for the other side would give better support for the right hand. All in all I would recommend this to most guitarists as a superior alternative to the traditional foot rest.