I am quite tall

[ROBINDESBOIS]

Which is stronger I am quite tall or I am tall? I mean who is taller.?

[Premium]

quite = bastante

So "I'm quite/pretty tall" would be superior, I guess.
Let's see what native speakers have to say.

[Perikles]

Originally Posted by ROBINDESBOIS

Which is stronger I am quite tall or I am tall? I mean who is taller.?

The qualifier "quite" is very subjective. "I am tall" is an objective statement, but the other isn't. "I'm quite tall" could be an extremely tall person admitting to the fact with an understatement when he can't find trousers big enough in a shop. But it could also be somebody who is small, but not as small as somebody thinks he is and needs to stress that.

So the answer needs a context. As usual

Edit: the original meaning of quite (from M.E. quit) is completely. But there is another meaning from 19th century of fairly. Which one is meant depends on context. It makes no sense to say somebody is completely tall, so it must mean fairly tall. But if I say this towel is quite dry or I am quite content then it means completely. There are times when I have no idea which is meant. He was quite polite could mean he was extremely polite or fairly polite, depending again on context.

Anyway, it is impossible to say which of the above is taller. Are you quite satisfied with the answer?

[chileno]

Pericles is correct.

Consider the following

Soy bien alto.

Soy bastante alto

[poli]

I agree with Perikles and Chileno, but would like to add my .
If you substitute quite for very, your meaning will be less ambiguous (at least in American English). I think quite is used less frequently in American English.

[rom2894]

I think in general "quite" tall is used to express the fact that someone is even taller than normal standards of being considered tall. It would not normally mean that someone is fairly tall or a little tall. If someone is "tall" he or she is taller than the average person. If someone is "quite tall" than they are probably expressing the fact that they are taller than the average "tall" person.