They've still got a chance to win the league, which is a far great accomplishment then winning the Carling and the FA (if we get it) and they'll be playing in the Champions League next season. Not to mention they are going to receive more revenue, and be able to attract better players thus leading to more success down the road. The cups are nice, great even, but they are short term successes, we need to set ourselves up to be successful in the long term. Best way to do that is to be top 4 and be competing in the best competition in soccer.
I cannot honestly believe you'd take our season over United's so far. Especially considering they have a chance to win the league. Even if they don't, I'd rather have the opportunity than the Carling and a place in the FA final.