I just bought these shoes today at my local New Balance store so this is maybe a little soon to know but these shoes feel SO GOOD I am compelled to praise them after my first 20-minute walk tonight. They needed no break-in at all, for me at least.  Have an arthritic knee and have found on my own that barefoot walking on my wood floor at home is the kindest to my knee--actually helping me to recover from about 6/10 arthritis pain to 1 or 2/10, so I haven't had to have the knee replacement I thought was a sure thing a few months ago.  Needed a shoe I could walk in for exercise and also use to travel, and this is really, really comfortable.  Vibrams are way too minimalist for me, so these are perfect.  I'm wearing about a 1/2 size larger than I usually wear in a running shoe (a size larger than my street shoes).  This has a nice roomy toe box and is a good fit for my narrow heel.  Was already somewhat used to a flat flexible, minimal support shoe (have been wearing NB 661--now discontinued), and this feels even better for my knee than that one.  Thanks, New Balance!