Id like to play with one of the big 4 however through observation and experience.
Never actually played as the Selucids, but they do look far too easy, Crazy research, crazy money and access to all military units this all despite the initial manpower issues (which you could always supplement with merc's). The romans, heh can anyone actually lose with them ?. The carthaginians, gobble numidia then its easy street. But the country that i find easiest of all is Egypt, they have so much manpower to throw at any problem and enough cash to destabalise any none Senate based government out there.
Think I will have to investigate Epogni patch finally to get a satisfying game with any of the 4 major powers. Although might be prudent to wait til the cascade bug is fixed.