A full afternoon of searching has got me nowhere with this question so its time to turn to the wise voices of experience.

I have a MM-140AS that I'm getting ready to consign to Craigslist. I'm also going to order an MM-211AS to replace it. So for at least a while I'll have both machines

My 140, which I've had for a couple of years has the original M10 gun with it. I notice that Miller now ships it's smaller MIG units with the M100 gun. Naturally because I expect to have both in hand at the same time I'd like to keep the better gun and let the other go with the sale of the 140. The thing is I don't know that there is any difference between them other that one has a red trigger and the other's is blue. I suppose that given a choice I'd pick blue over red but is there really any difference between the two?