It would have been a disaster for the Allies.
Imagine asking the French soldiers, Italian, all Continental Europe soldiers to forget and forgive their burned villages, raped women, deported and slaughtered population and now fight alongside the SS against the Heroes of Stalingrad…
As mentioned, if the Allies would have been the aggressors, the Communists in all country would have at minimum sabotage all war effort as they did during the Indochina war in France…
In 1945, France started the Indochina war. De-colonisation was on.
The soldiers were tired of war and wouldn’t understand why to fight former allies. We are not any more in the 16th Century when shifting alliances was possible by the King’s will.

In pure military aspect:
The JS1 & 2 would have pulverised the Patton and other Comet. The Soviet had as well their own jet fighter, as it was revelled a later one in Korea (Mig 15 every one) better than their western equivalent and absolutely independent from the Me 262 design. We know now they started their experiment in the 40’s.
In term of military might I would agree with Panzer. The Soviet fought against full SS Corps (Budapest) and won. Not against Wolkstrum and 2nd or 3rd rank divisions.
Naval superiority against USSR would have been a waste of money.
Division from the Pacific front: So at what date do you want to attack: After the Japanese capitulation? Guys, we won this war and let start this one?
If before what would happen with the soviet Forces which attacked the Japanese in China Manchuria.
I can imagine the Soviet Air Force attacking the B29 over Japon…