Looks just like AoE III
:I
This has more units and building varieties, much more variance between the "civilizations" (from what I've played of civs other than ZE GERMANS in AOE3 they all are much the same, just with a slightly infantry/cavalry/artillery shift between them), a more fleshed-out tech tree, more units with actual special abilities, etc.
Also the AI in this will actually kick your ass, whereas in AOE3 it was below par (I won my first match against 3 hard AIs and got least resources, and I had resources to spare all over the place, and consistently win similar matches - I've never beaten a Normal or Hard AI opponent in Warcraft III or for that matter Starcraft)