My first impression of Guu when I walked in the door? ALARMING! There should be a warning posted outside that you will be yelled at upon crossing the threshold. I mean, it's a neat idea I suppose (though, I can only imagine they have a constant supply of ricola in the back...not sure how they don't all lose their voices within the first couple hours of service) but it grows tiresome very quickly. This place was hopping when I went last Friday so there was someone walking through the door every minute or so!! If you're looking for a relaxing dining experience or if you really care what your dining compadres are saying than this is not the place for you! There was a lot of smiling and nodding going on without any comprehension as to what my friends were saying to me. Note to self: Get hearing checked.
Volume level aside, Guu is a very unique dining experience that I definitely think is worth trying out. We sat in the "traditional" area of the restaurant where you are asked to take your shoes off (bring your least holey socks!) and sit on the floor. You could sit on your feet I suppose, but there is space underneath the table for your legs...so it's pretty much like sitting at a booth.
As other people have stated, the wait time for your meal can be quite lengthy so you shouldn't go to Guu ravenous - a pre-Guu snack would be wise! However, the food is well worth the wait! I particularly enjoyed the deep fried brie (A MUST!) and the pumpkin croquette.
The service was slow, but that's only because the restaurant was jam packed full of Guu-nies. In spite of slow service, the wait staff was very helpful when they were around so that made up for long periods of absence.
Be aware that they do not take reservations, so you're going to have to get there early if you don't wait to wait for hours for a table. As we were leaving the restaurant around 8:30 there was a hoard of hungry people lining the entrance. It was madness!