I'm playing on Prince now... It's been quite a change from the previous level... I've only managed to win one game as Elizabeth, and it was a tiny map- only four of us. Gandhi only built one city, and although Suleiman had taken Beijing, he was embroiled in a war with China when I struck from the other side and took Istanbul.
Earlier tonight, I tried playing as Assyria (just bought the DLC), and while I beat America after a long war, Arabia used a Great Artist to bankrupt me and make my populace Livid at the same time - all my ground units were disbanded, leaving me with just cannons, so I threw in the towel. Maybe there are a few bits of genius in the AI.
My biggest failing is I seem to be having happiness and/or money issues, not to mention falling behind frequently in the tech race. Other than that....
I probably wouldn't last fifty turns against half the posters here. I never was more than a casual player in Civ 2, 3, or 4. I doubt even if I do get the hang of it, that I'll ever go to a higher difficulty.
So, you'll never hear me chiding someone else's difficulty level.