absolutely amazing stuff! ....and on some songs they have .PDF files of tunes and transcriptions. There is wealth of material here that could keep you busy for months.
I do recommend using either RealAlternative or JetAudio for playing files, and Foxit PDF reader (free) instead of Adobe Acrobat, as it loads MUCH more quickly.

(Note...if you do try Foxit, you must 'associate' PDF files with it in order to have it open on a click, or first save them, then open Foxit and go to where you saved it. It ain't hard, and once you do it twice, you'll wonder why you put up with Adobe.)