The software recognizes which tone to play and in part on which string, recognizes the error and displays it accordingly. If you make progress, the songs are heavier and so can you with some practice soon learn new songs, or get close to tricky solos. Especially for beginners an ingenious concept!
Even properly creamy is the shop. Depending on your taste, you can expand the arsenal of songs from Rocksmith. Here's some more songs. Unfortunately not all the songs, but more than you need to get ready for a cover band.
I've searched and wanted to find negative and I must say for me is the cable has fallen a bit short. But if you have even the urge when you have to play a little expect that you unceremoniously pulls a couple of times on the PS3 to move - but I think because I own fault.