I still play it sometimes, for old times sake. I particularly like the Mongols and their fast horse archers.
I agree that AoE 3 lacked a few things compared with AoE 2, but Age of Mythology on the other hand came really close to the same feel. I recently went through that whole campaign again, because i just recently installed the Titans expansion, and i wanted experience the whole thing again right from the beginning.
But since i discovered Company of Heroes, i have all other RTS games on hold, simply because it's nothing like i've ever played before, arguably the best RTS ever. It cost me a few nights of sleep in the last week.
