I've been playing them in order, and the interesting ones more than once. So far I like the Mesopotamia flavor the best; I really feel like we're back at the beginning of things. (Could we start epic games that way?)
RoR is another fave, but it's odd that Persia seems more fun than Rome. The FoR has its own crude charm.
I didn't like the middle ages at first, but now that i understand the tech tree(s), wonders, relics, kings and uu's, i've done it several times. With so many very different civ flavors, it's got loads of replay value. The Viking game is way different from the christian or arab or Byzantine games... (Is there a way to play the unplayable ones? But maybe they're not worth it.) One oddity to me is how reluctant all those 17 MA civs are to make alliances, after the wild, frequent shifts in ROR. It's safe to attack again, without people joining the enemy!
I'll vote when i've done them all (probly sometime next year.)
One drawback to the conquests is that now the epic game is bland, predictable and boring, and lacks several excellent refinements and units. The lower corruption/waste of AoD, for one thing. After seeing how much better overseas colonies work with that, it's hard to go back to the nasty, repressive deadening waste, draining the lifeblood of all civs, brutally quashing development, expansion and innovation, bleeding your hard work into the ground, just a few steps away from your (usually poorly-placed) founding city.
Do I still count? 
.
is great.
