I ordered same exact size as my running shoes and the boots fit perfectly.  I wear a size 10.5 regular running shoe which is what I ordered with the Mini-Mils.  Normally for Belleville's or Altama's I would order a 9-9.5 regular.
I have never worn minimalist shoes before so these were a bit different at first.  There was some break-in for me in the top of the heel section, almost to the Achilles tendon area.  I have been wearing these all day for the past four days or so just walking on hardball with little off-road use.
The more I wear them the more I like them.  I have not had a chance to run in them yet which I am looking forward to trying.  I am strongly considering buying a second pair.  I would not do any heavy pack runs with these.  I will try a lighter pack run and see how it goes.