best(on a relatively high lvl. - immo/emperor or so)
early period
#1 - sumer. The vulture is a swordsman on steroids and most important, he does an excellent job at handling both archers and axes in a city assault should you early rush(if he'd been aggresive instead of protective things would be really gross
); creative means you can block anyone at your leisure, combined with zigurat at a measly ammount of beakers away means you won't care too much about maintenance should you have to go some 15 tiles away from your cap. with your 3rd city or so in order to seal off someone. With enough wood in your cap. bfc. might even get oracle since priesthood is natural for you. Protective is meh, though probably you can run some drafting since ce ain't a must with him(though I always prefered ce, thus I pretty much hate protective as there'd be few opportunities to draft).
#2 darius - financial - best trait in this game; organized - damn good trait too. When you see -2 when founding your 2nd city instead of -3, it really feels good - now, 1 commerce might not be much, but 1 commerce in -3k is a whole different thing then 1 commerce in 1.5k. 1 commerce back then is probably 5-10% of your whole income. Furthermore, it's half the ammount of hammers courthouse.
The starting techs are good(I don't mind hunting when paired with something powerful like agri) and perfectly combined - cheapest possible ah research(since you start with both prereqs), then wheel, then connect the ponnies, then rush if there's anything to rush
#3 HC. He's definitelly the best thing hammer spent/conquered city if you want an early rush. Both traits are great, with fin. being my fav.; early stonehenge is good. UB is decent(though without expansive, he's soooo many miles away from a creative leader since that terrace really takes it's turn to be built). Starting techs are good and pair well with his traits. I mean, you can do half a stonehenge while you wait for poly to be researched if there's nothing workable in your cap. bfc.
Not having to worry about barbarians for quite some time is super.
I only rate him 3rd probably just because I did so many q rushes in warlords I got bored about him, so didn't play him in a long time
#4 1 of the caesars. pretorians are pretorians... even a 3 years old child could use them...
worst... anyone with 2 of protective/expansive/imperialistic; and obviously saladin, since, while spiritual is quite strong, the ub is poor, the uu is crap, the starting techs are a miserable combo. Also monty - while his ub might be great, his starting techs are horrid and his uu is... like, gimme back the swordsman, thanks... Post bts, brennus too, since charismatic is way less powerful then warlords.
whom I don't like - the greeks. I consider 2 types of war - early rush, where he doesn't have any SoD and normal war. In an early rush that phalanx doesn't help - it still has str 5 and is weak on city assault vs. archers which are dominant and 100% vs mounted units is solved by having the decency to keep 1-2 spears in your SoD... In a normal war, after waiting for his SoD to get inside your teritory and trashing it(just build catapults... if you lost, you didn't build enough catapults or you didn't wait for his SoD), it's again all about what's faring best in city assaults - hence why I don't like the chinese or hre uu's either.
Hence, as UUs, I'd rate as good immortals, quecha(for being cheap), vulture, zerkers(especially since they retain amphibious when promoted, which helps when playing contients or anything with naval invasions) and things like that. Obviously pretorians, but I hate playin' romans... feels like cheatin'...