I've been wearing 608v2's for quite a while and the MX623 appeared to be a step up from that model. Not! Insole at the ball of the foot feels alot harder. Also, the right shoe felt as though there was a lump at the ball cushioning area, suggesting possible quality issues with the construction. I work in the medical field and am on my feet 8 to 12 hours a day. As soon as I put these shoes on and walked a bit I knew these were going back. All the other New Balance shoes that I've owned felt great right out of the box, so if they don't feel good, I'm not going to risk trying to break them in at the expense of my comfort.