GPU mining will always be feasible, it's just getting brought in line with CPU mining. Seems like a bit of a shame to me because adding more GPUs is a much more costly / involved process than adding CPUs (in terms of finding computers with existing usable hardware, let alone botnets).

After the latest drop, GPU is still far better, but if it keeps dropping more (I have no idea how much further it has to go) then that could end up in a weird place.