Terrible construction.  I've worn New Balance shoes seemingly forever.  Every pair I've had before or after these have been excellent.  My MX623's are the worst constructed pair I've ever owned.  The seams split very quickly, as in 10-12 wearings, along the lace panels, then where the leather meets the sole around the toe box.  Now I have expensive lawn mowing shoes, at least for a few more wears...