The first thing you really notice is the atmosphere. Its very loud and upbeat due to the music and the staff cheering in unison every so often. It's quite nice if you're okay with noise and all the staff communicate with eachother in Japanese.
The price is alright but definitely expect smaller to medium portions (especially with non-main dishes). If you're looking for a full stomach on a budget, don't come here. The two times I've been to Guu were for birthdays, and I can say that if you're willing to pay the (reasonable) price the food is delicious. They have group meals (i.e. 6 can dine, etc) but the conditions on these are quite restrictive. I'd recommend the bibimbap, though it takes a while to come.
Overall, it's a great restaurant. I wouldn't eat here regularly but if you're ready for some noise then this is definitely a place you want to try.