Went to Guu last week in a party of 5. Didn't really know what to expect because the only Japanese restaurants I have been to previously were AYCE sushi places. The atmosphere was awesome at Guu. The staff were energetic, loud and friendly. The menu wasn't very well-suited for me personally as most of the items seemed foreign and/or unattractive, but I tried a variety of items and everything was quite tasty.
4/5 stars, I'd go back occasionally.