I have the free acoustic one and since I play guitar I wanted the rock one. I thought it would have different tones and frets but noooooooo! The thing doesnt even have 6 strings! I was so mad when I bought this! Biggest waste of money EVER! Most of my favorite apps only cost 1$! I want my 2$ back stupid apple! NEVER EVER BUY THIS APP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!