Egypt was quite an interesting campaign. VH/VH, I crushed Kyrene in less than 8 turns. Kush was a similar matter, and then I thought of dealing with Babylon, but I focused more on Greece and Italy instead. Took quite a while to absorb oligarchy, and the enemies I faced were numerous and wealthy.
Egypt's army is fairly diverse, and quite handy. The mercenaries helped a lot, of course, as I recruited nearly everything I could. But the chariots and hoplites, they were on par with spartan hoplites with the proper upgrades and experience. Also, it was damned hard to maintain order in all of my various domains, because buildings to maintain order for Egypt are few indeed. Even changing my capital didn't really help, so I just kept Sais as the capital the whole time.