Ey-up Bri Just noticed this thread, I was going to post something similar - my mate wears mizunos, has started to get back pain a bit now and is putting it down to the trainers been worn. We worked out that they've only got 300 miles or under in them, which is a bit crp to be knackered.
Needless to say he's going to move away from them now. I had heard that mizunos don't last as long as others, would suggest RB may be able to give gospel advice though!