If you haven't played any before and get GH3, expect hurted fingers by the end of the day... mine still hurt from 5-6 hrs yesterday
And there was me expecting being a (bass) guitar player would help me loads lol
EDIT: Remember to take breaks, no matter how much you're pwning! I've got blisters from repeated bashing of the fret buttons, and I've only had it 3 days!