I bought this as I needed to practice chin ups for gymnastics. I found it a great piece of equipment, for both beginners and those more advanced.
Easy to install. Screws supplied, but not needed. Holds you up by friction, and just twist one side to shorten or lengthen it.
Comfortable - padded grips
Durable - holds well, but make sure it's tight enough!
Makes marks - but go away with a little kitchen cleaner and a wipe
You can only lengthen one side, so the padded bits won't always be in the middle.
Good luck, this is definitely worth the money and a great buy! This is the best I've ever had.