As a previous owner of the NB 1223, 1224, and 1225, I was disappointed at the reviews of the 1226.  Luckily NB also offered the 1260 as an upgrade.  Compared to the 1225s these seem to be of slightly higher quality and comfort with one exception: The cushioning under the forward part of your foot feels thin.  It's not that the cushioning isn't adequate, but it does feel thin and slightly firmer than the 1225.  I do get a better sense of the terrain I'm moving across, but I do think that it encourages you to land more on your heel as a result.  Perhaps the firmer cushioning leads to a longer-lasting sneaker - the 1225s did tend to wear out after a few months - but I've gotten used to the softer design.  If the cushioning were slightly thicker I think these would be a great pair of sneakers.