I've been wearing 623 since version 0. Here's a summary. V0 - 2 pairs, very comfortable, leather upper, very good detailing, great shoes. 2 pairs, good wearing comfort, leather upper, details removed, slightly smaller, normal shoes. V3 - 1 pair, bad comfort, hard synthetic upper, terrible, terrible shoes. V4 - stick a fork in, I'm ready. Not there. The upper of the V3 is made of a very stiff plastic. The toe box flexes downward and cuts into the top of the foot as you walk. I hoped that…