The original FA, almost none.
For the latest versions depends on your abstraction, ThunderKittens[0] provides about the same speed up over FA2 (1.3x-2x%) as the article but relatively universal across GPUs. For any new hardware there may be hardware specific features that make it edge out more performance; usually vendors will adopt any new features that seems to beat them, but you do get fragmented API/libraries (which is already true for CUDA).