Were you able to try them on? did you try them on with big/multiple pairs of socks? if you can't try them on, i would go w/ my regular size. you can always put more socks on once they are broken in but who wants tortured feet for the first couple of seasons?
the problem is, my reg. size is NOT available
I went with a size smaller when I got my boots last year and it was snug at first but after riding all day in them, it got very uncomfortable... I had to go and get my size. After I did that, it felt oh so much better... so I would say, dont go smaller, because it may not break in and your feet will kill you when you ride....
with most snowboarding boots my feet kill me anyway. I can't go bigger... I can't try these on, either...