When I went from regular tires (2 new, 2 worn) to LRR tires, the difference in city was AMAZING! I didn't expect to be able to ...roll... as well as I did!
I went from having to let off 35MPH to get down to ~15 at the end of the road and the new tires would get me ~10MPH more by the end of the same stretch! This also included a wheel swap to wheels that were slightly lighter, but shouldn't have made that much difference in coasting like that (especially since the new wheels are much less aerodynamic).
According to some of my notes at the time of the swap, I gained 2-3MPG going to the LRR. I can only assume that's city, simply because the majority of my driving is city.