Invite some friends over and bust this game out. They will j!zz in their pants.
Brilliant tracklist
Surprisingly good audio quality - the PS2 version wasn't shafted in this area, thank god
Quick loading times
Bass Groove - tells the bassist to KEEP GROOVIN' ON SOUL BROTHA
Cowbell
CONS
There's a freestyle drum mode, but there should be a freestyle mode for all instruments - not like the counterintuitive song creator in GH:WT, but a live, garage band-style mode with a bunch of preset sounds for the instruments. Obviously guitar will be toned down with only five frets to use, but come on, people made songs using the GH3 cheat screen for crying out loud.
Kick pedal during fills registers onscreen, but without sound - maybe an oversight?
No character customization - who cares, when I see the onscreen drummer, I get amped anyway
NOTES
You can tell Harmonix is a team of music lovers. You really have to PLAY every song before you judge the tracklist. Even songs I thought I wouldn't like were extremely fun. Huge props to Harmonix here.
Most fun with 3 or 4 players, though 2 is still fun
Headphones or good speakers a must
The kick pedal thing was actually awesome during E-Pro, the pause when I wanted to use the pedal ended up going perfectly with the song. :D