The mech on the right would be impactical in open terrain warfare unless those legs have large wheels on the bottom. However, for something like enclosed warfare such as in city streets and forests, I believe that one would shine.
You know, this is the first time I've seen your quick sketch style. Now I have to say, I recognize some of the other pieces of artwork that you ended up doing, elsewhere. Namely involving stomping furry-raves and Victors with Long Tom arms.