I've worn both Asics and Brooks for years but leaned towards the Asics due to their softer feel. Ordered the 2150 since the Foundations 8's are being replaced by the 9's. This shoe runs a full size narrower than my F8's. Tried it on and knew right away that it did not fit, even though it was the same size as my F8's. Held them next to each other with the soles facing upward an you can visibly see that the soles of the 2150's are not as wide. So this is how you take 2oz out of what is basically the same shoe? Sent them back and ordered the F9's. I hope they work since I read another review that stated the new Asics running shoes are now more narrow than before. If that's the case with the F9's I'm going back to Brooks.