I'm copying my Kaiju post from another thread...
I have 2011 Nike Kaiju, and I can tell you that the boots run small. You'll have to buy slightly bigger size (most likely 1/2 size bigger) to get a good snug fit with toes barely touching the front of the boots.
To get a sense of your "true size", you need to remove the boot insole (removable inner liner) and measure it in centimeter (to convert inch to centimeter, multiply inch by 2.54). Compare that to your foot measurement (draw the outline of your foot on a piece of paper and measure the length). We only confuse each other by mentioning that we buy bigger and/or smaller from our street shoe size - which has no bearing on what our actual foot size is.
My foot measures 10.25 inches or 26 centimeters (or 26 mondo size). When I take the insole out of my vans contra and measure it, it is exactly 26.5 centimeters - so wearing socks, my toes just barely brush the front of the boots, a perfect fit.
However, for my Nike Kaiju, I had to go with size US 9.5 (or 27.5 mondo/centimeter). How can that be?? Because when I removed the insole and measured it, the 9.5 Kaiju's insole measured 26.5 centimeter -- even though the label states 9.5 (which is 27.5 mondo/centimeter). There is no consistency in boot sizing !!
My recommendation to everyone who shops online because your LBS does not carry the boots you want is to have the seller/online merchant measure the insole and send that information to you. You should buy the boots with the insole that is 1/4 to 1/2 centimeter bigger than your foot size.
Happy Hunting for your perfect boots.