Loving the game, but a few things are holding it back from it being great.
1) The guitar is terrible. My 1-black fret is squeaky as hell. The wireless dongle is really bad...it occasionally suffers from interference and my strums will lag for good portions of some songs.
2) Calibration. Let me set values myself instead of relying on vague auto-calibration. Even after I've calibrated it, it still feels like there's more lag than even Rock Band PS3 (and PS3 has innate input lag that PS4 shouldn't have, so I expected this to be better than that).
3) No ability to play with friends online.
4) No ability to compare scores with friends.
Besides that, I'm not completely sure how I feel about the new button layout. On one hand, it's something new to learn and makes simpler rythm songs a lot more fun. On the other hand, I feel like it's not very intuitive and the skill ceiling might just be too high on Expert. I don't know if I'll realistically be able to sight read anything on Expert, regardless of my play time. Bar chords really throw a wrench into the whole thing, especially when combined with other notes.