G-Man
It's so true, I've had to relearn over 20 songs and although it isn't completely new it is still enough of a challenge to be interesting. It forced me to find out what notes I need to play and what "sounds right" for each song, and it isn't necessarily what I used to play for the rhythm on guitar.
It's very interesting how the drums interact with the bass, I can see now after a few months what everyone meant. And the joy of not having to fight with vocals and the other guitar for volume is amazing.