the milspec tube is 1.14" O.D. and the commercial is 1.17" O.D.
It may make a difference if you find yourself bashing things often with the butt of your rifle, or if you feel you need to slam the butt on the ground for some reason. Otherwise, for just plain shooting, a commercial tube will suffice, as long as you are happy with the stock/stock options.
The inner dimensions are the same for both a commercial buffer tube or milspec tube.