Here's the WW2DB article on Rokossovsky, to add more info to this discussion:
WW2DB: Konstantin Rokossovsky
One interesting thing about his military career during the war was that he had equal chance as Zhukov to capture Berlin. Koniev, too, was in the running. In fact, none of them really knew who was going to have that honor -- Stalin was pitting them against each other for the same objective to compete for his favor.