Most of the sources I've looked at suggest that the troops were very well-motivated, and in some cases jubilant, in the taking of Berlin.

It is true that the Soviets lost around 80 000 troops here (a figure which was greatly inflated due to ferocious fighting from German troops, who knew what the loss of their capital city represented), but when contrasted with overall casualty figures - approximately 8 700 000 Soviet military casualties alone over the course of a four year conflict - the losses at Berlin look like a blip.

The soldiers, who had seen their friends, family members and loved ones shot, tortured, starved and gassed throughout the war, were well-aware that taking Berlin was the final push in shattering the Third Reich. This helps to explain the looting and mass rape of German women which characterized the end of the Battle of Berlin.

Edit: Sources

Catherine Merridale, "Culture, Ideology and Combat in the Red Army, 1939-1945," Journal of Contemporary History, Vol. 41, No. 2 (2006): 305-324.