DD is 6.5 and has been riding in her GN as a booster several months. Yesterday when the new FR85 arrived she chose to use the harness which she has about 1.5" left in. I really like the GN as a first booster for her. We have a TB too, but it's just a backup. The belt guide is great on the GN. It fits her well, can be LATCHed, has deep sides so she stays in position, has arm rests but the belts aren't routed under them, and the rigid back doesn't move as she pulls the belt to buckle. I can see where the height could be an issue for some kids to buckle it though. I haven't tried the FR in booster yet. I just go with whichever is more convenient now. She has to move outboard soon to a spot without LATCH so the longer she is harnessed, I won't have to worry about securing a booster. All spots have TT so no difference in safety there.