Regarding Zhukov:
I have been reading some books written by David Glantz for some time. (He should be familiar to those who like reading about the 'Eastern Front' in detail.) According to him, Zhukov's biggest fiasco was Operation Mars, which took place during winter of 1942, aimed at cutting off the prominant German salient facing Moscow.
By the numbers, lot more troops and tanks were used in Operation Mars than Operation Uranus. Therefore, the former was the 'main' Soviet winter offensive of 1942.
Problems with Operation Mars:
1. A lot of this had to do with more heavily forested terrain around Moscow, coupled with the static nature of the battles in the north and the center. The Germans had a plenty of time to entrench and fortify.
2. Unlike Stalingrad, the Germans had a handful of fresh reserves (Panzer Divisions) to reinforce the Rzhev salient.
3. While German Sixth Army was led by a mediocre man known as Paulus (I think he was a good staff officer, but his forte was not in command), German Ninth Army was led by Model, who was among the best senior commanders the Germans had.
4. The initial Soviet onslaught towards the western flank of the Rzhev salient looked promising. However, the other pincer (Soviet Western Front, led by Konev) bogged down.
5. This is where things got pretty bad: Zhukov committed second echelon and exploitation forces to reinforce the first echelon. With forested terrain with limited roads, massive congestion resulted. The Soviet losses were staggering. Yet, they failed. The area of operation was too small and congested to allow operational freedom.
(Zhukov got into the same lapse at Seelow Heights in 1945.)