it's funny, because I'm sort of a case of "evolution" in this matter... started trying NTB when I started to win my Monarch games, mainly because I am tired of no differentiation between civs in terms of research (in my view, this is the main effect of tech trading, and not a good one if you ask me).
So, after a couple of tries with NTB, I found that the difference was not as big as I wanted or expected. Research slows somewhat, but in the end, the whole tech whoring still takes place.
So, when I jumped to Emperor, I decided to go the way of No Tech Trading at all. And man, now that's a difference! As somebody suggested earlier, difficulty levels (higher) give the Ai a big advantage in resources, so they usually are ahead of you in tech. That makes for a huge challenge in Emperor +, plus you start to see real difference in research between civs. Add to that setting Random personalities (so that you cannot know what path every civ will take), and you have a hell of a game!!! Believe me.
Now I'm thinking on disabling cultural victory also, because I find that some civs go for it "full monty". If you are prepared to deal with such scenario (hehehe), there is no way they can succeed because they divert all resources to culture, and even if they had a tech lead against you, you can cath up, build up your military, and raze the cultural bastions to the ground.
I imagine a nightmare for my civ if that does not happen. SO I will probably try next time.
So, try Emperor with NTT and random personalities, and you will experience what I think true civ is.
Cheers,