Visited Sep. 29, 2012.
Graffi is a fairly standard grill but I had read several reviews that rated it as the best hamburger in Trondheim as well as having extremely rude servers. I found both of these statements to be false.
It is comfortable and quite busy. I carefully observed the servers interacting with other customers as well. I found them to be polite and helpful, I never saw them act rudely toward anyone.
On to the burgers. First, the patties were not well-formed, very lumpy and almost like two meatballs sort of smashed together. I found the seasoning off-putting. he buns had integrity but were a bit hard and were way too large for the size of the hamburger. I did not like the cheese used on the burger at all. I chose to leave the salad off on the side as I do not like very much on my burgers and I have noticed a tendency toward overdressing here. I ate the salad as such, I found it okay and a bit less heavily dressed than many. They do a very good job with their french fries, they were very slightly over cooked. Very crisp and without any seasoning is a perfect fry for me, so this were close.
Basically, the restaurant was okay. I would try other foods here if I had occasion to dine here again but I would not get the burger again. I also would not go out of my way to return.