The Superblast is the odd one in ASICS' range: a huge stack of foam with no plate in it. The 2 puts FF TURBO PLUS, the same foam as the Metaspeed racers, over a bouncier base, and the result is a shoe you can run long in and still run fast in.
It suits runners who want one shoe covering long runs and tempo work, and anyone who likes the ride of a super-shoe without a carbon plate underfoot.
It is not a racer - with no plate you do not get the snap a race shoe gives you at the sharp end. It is also the most expensive trainer ASICS sells, and at 250 g with that much foam it is a particular taste rather than a first pair.