Almost everyone I know would say that I am most likely to "tell it like it is". Whether my tone of voice gives away my true meaning or by saying something passive aggressively, I am sure they are right.
I have noticed a huge difference between the British and Americans on this subject. The British are very good at holding their tongues almost to a fault, in my opinion. But they would say that Americans are too good at telling it like it is.
Personally, I think it is good to tell it like it is, however, are you really "telling it like it is," or are you telling it as you see it? Everyone's view of "as it is" is different and therefore you are really just giving your opinion, which is horribly skewed and therefore can come across as mean and misguided.