The Magic Speed 5 is the biggest single-generation change in the line: roughly 50 g gone, down to 196 g, on a platform ASICS lowered by 6 mm at the heel to a 7 mm drop. A reconfigured carbon plate runs through FF LEAP and FF BLAST PLUS foams — the plate-you-can-train-in idea, now in a shoe that weighs like a racer.
It suits you for tempo days, intervals, and races where you are not spending Metaspeed money — the same brief as the 4, executed much lighter.
It is not a daily trainer; the plate makes easy running feel forced, and the price crossed into premium territory this generation. And it is still the sub-flagship: at the sharp end of a goal race, the Metaspeed remains the shoe this one is imitating.