I just got my Engineer 12R, I love the hight of the shaft, the rustic look and sturdiness. Well I was afraid when I ordered "Carmen Harness Tall Boot" after reading some review about the engineer style I ordered bigger and the reality they are true size as the Engineer are, now  I ordered 9M that is my correct size.  However, sometimes I order 9.5 - 10 because of the style of the shoes.  This one are true, true size, but you have to stretch them; I left the boot with an empty bottle of wine in each overnight and soak them with little alcohol that is good to stretch shoes but, has to be a good quality like this one.  I am using it now and they are perfect, I love it because I now this one will last forever.  Think about it size 9 and still room for my toes and with cashmere socks.  One advise a shoehorn is a good tool for tall or sturdy boot owners!! Now my Carmen are lose but still beautiful I order one size bigger. I hope this review help you to decide in your size, ahh! and this one (Engineer 12R) are made in USA something that I really appreciated because any product made here is excellent and superior quality.  I don't mind paying if is good, if you don't have enough money now, save!! is worthy.

Updated 12/18/12
Just I want let you know be careful with the alcohol deal with light colors. Alcohol sometimes change the color, I have a pair of Born flat "lemon yellow" that changed to darker.  In the case you will be better buying the spray to stretch shoes.
I continues to be in the honeymoon stage with my Engineer 12R!! I have it in Gaucho Crazy Horse.