I bought these to use as my regular trail runners.  I have a pair of New Balance Minimus road runners that I really enjoy, so I thought I'd stick with the brand.  In my experience, NB always runs about half a size big.  I normally wear a 12, but in NB I always go for an 11.5.  This has worked well for me in all of my NB purchases (including my Minimus road runners).  These shoes, however, seem to fit pretty much true to size, meaning that the 11.5 I bought is rather tight, particularly in the toe box.  This isn't a knock on the shoes, just something to be cognizant of before purchasing.  I stretched them out using shoe trees and wore them around the to break them in.  Now with thin (or no) socks, they are snug but manageable.  If, like me, you are used to going half a size down with NB, I would suggest sticking with your true size for this model.