I have never played a real guitar, I never practice (I play a couple songs a week), but I manage to get 97-99% on almost every song and FC almost every solo. I improve when I am not playing GH.
Guitar Hero Metallica is the best thing that ever happened to the franchise. Metallica is my favourite band. \m/ forever.
The FC's elude me; I always choke in easy places and hit all the hard parts. My best songs are Evil and Whiplash, but my favourite song is Fade to Black.