I like the 4-3-3 in principle but it really requires a very reliable goalscorer in the middle which we don't have.
Notice how MUFC have had a poor goal tally this year and how Portugal used to dominate games but suffered because Gomes and Pauleta (?) were very average in front of goal.
It worked for Chelsea because when required they also got their fair share of goals from set pieces and from midfield, mainly Lampard.
I'd be inclined to stick with an attacking 4-4-2.
By the way, I thought our set pieces were much better on Saturday.