I have always enjoyed the old malt shop feel at the themed burger restaurants. Ruby's, Fatburger (although not that themed) and Johnny Rockets. The first and last are more restaurants then fast food however.
I have recently visited the Johnny Rocket's across the street from the Hard Rock Hotel and like always, I thoroughly enjoyed my time. However, as some posters have stated, you do pay a premium for the atmosphere. This is not a "quick and cheap" burger like McDonald's, but more of an experience. Something you may only do once every two months.
The woman that helped me was kind and courteous and I wish I could remember her name. She was quick and attentive and on top of her game when it came to refilling my drink. My last go at the eatery was a Chicken Club Sandwich, with 1/2 and 1/2 fries and onion rings. Splitting the rings and fries is great, but I sometimes wish I had more rings, so maybe next time, I will get the rings alone.
I have also noticed some new menu items (at least new to me). One of these items is a cobb salad and I can see that as a big seller if people aren't interesting in eating red meat (or turkey burgers).
Overall, I have a good experience with Johnny Rocket's and I will continue to go there in the future.