Took the plunge and skated a full session with Spitfire F4 Classics 54mm, not the fancy F4 stuff, after riding bones for close to a year. Got to say I'm very impressed and kick myself for not trying them sooner. The slide on ledges was very consistent and being able to roll over crust was much appreciated. They were wider than I liked, maybe I'll try a conical or tablet next in a 52mm.
Even the 99a felt better than the Bones Easy Streets which still felt hard and plastic-y.
My only gripe was the classics were red and coupled with my green graphic made it look like Xmas came early.