I've also worked my way up from Chieftain to my current status as Noble, and I'd like to keep it there. It seems stupid and unfair to let the AI have advantages just to make it harder (and besides, I like the difficulty until about the end when it becomes gravy).
This, and what you describe first, is exactly how I experience it. Noble and some bonuses to the AI is fine (competetive with no bonuses would of course be preferrable), but just letting them research faster and me slower and misc more bonuses to the AI, just doesn't seem like fun. If I get beat, and knowing it cheats rampantly, that won't feel like a fair loss. Of course it does need bonuses to compete...
I've played with the new aggressive AI of late, but meh, it ain't so tough (on noble). Sure it has more troops, but I was never a slouch at the military, have always played with raging barbarians on and run a balance between builder and aggressive warring so got little trouble being prepared. And I use my units a lot more effectively than the AI, as any human player do.
But I got this with most any game except shooters, that I tend to loose interest in later stages.
I try to use global settings that, while effecting human and AI alike, is most beneficient to the AI. Like having maps with some decent continental mass, as the AI blows at island-maps in my experience. Hmm, I'll go make a thread on that
