I can't say a lot about the rooms in Hotel Kopala, however the restaurant is great. I've been there about 10-12 times and always enjoy it.
The food is good, however in some other restaurants you can taste way more tasty Georgian food, but the view from the retaurant is breathtaking. The music is not loud , mostly soft piano music. Definetely great place to go for a lunch/dinner and probbly to stay as well in Tbilisi.