^^ Foot shape is a big factor, but that rings true for me too. I'm usually an 11, but I tried on a 10.5 in the 480 because it's all they had at the shop by me. It was too narrow across almost my entire foot, the volume was too low (the laces looked like they were about to burst when I tied them), and it just felt way too tight all around. I'll try them on TTS when I get a chance, but the length of them wasn't bad despite the width and volume being wrong for me, so it might just be the wrong shoe for me. Not just New Balance, but I find a lot of skate shoes are made to fit 'close to the foot' in a way that makes them the complete wrong shape and size.
I really like the designs and approach NB# takes to their cupsoles, but I've purchased some (913, 440, 1010) and tried on others (420, 808, 480), but I can't seem to find one that fits me right.