I've beaten every difficulty level at least once, and I have to say I prefer Prince. I prefer this level because I can play with any civ on pretty much any start and still win most the time.
I've also played on King/Emperor a bit, and can do pretty well, but even by those levels I find some mis-matches (Netherlands in jungle with only 1 luxury-type around; Aztecs in open grassland on a coast with no rivers; Iroquios with reasonable forest by the capital but no forest nearby) to be pretty rough, at least for me. And certain map types at Emperor especially are tough for certain civs... England on Highlands, Attila on Islands.
Beyond that, Prince also has a few hidden challenges. After all, the AIs have less gold to milk, and they often have a longer delay until they have multiple copies of luxuries for trade than they would at the higher levels.
I've also played on King/Emperor a bit, and can do pretty well, but even by those levels I find some mis-matches (Netherlands in jungle with only 1 luxury-type around; Aztecs in open grassland on a coast with no rivers; Iroquios with reasonable forest by the capital but no forest nearby) to be pretty rough, at least for me. And certain map types at Emperor especially are tough for certain civs... England on Highlands, Attila on Islands.
Beyond that, Prince also has a few hidden challenges. After all, the AIs have less gold to milk, and they often have a longer delay until they have multiple copies of luxuries for trade than they would at the higher levels.