I thought last night showed why Everton was a good move for Rooney. Watching the game, Rooney wasn't really that great. He was generally pretty cautious and even then managed to lose the ball a few times. Really lovely run for the goal, but in the second half with City down to 10 men and pushing forward, a pacy striker would have had a field day. Rooney offered nothing on the counter attack and the lack of threat meant City never had any reason to hold back.
Thing is though, the different expectations for Everton and United mean his contribution is seen differently. At United, losing a lead at a main rival despite being a man up would be seen as a poor result and so Rooney's lack of threat in the second half would stand out. At Everton, a draw away to City is seen as a decent result, so people don't worry so much about the second half performance and just focus on what he did well.