Letterman>>>>Leno

Leno probably has better writers/material but his sense of humor is lame and his interviewing and interacting with the guests I mostly find extremely embarrassing.

With Letterman I never bother with the opening monologue which is almost never funny, the good thing with David is that he seems to know that and can make fun of himself, and then often when seated at the table where he rambles on about whatever, he can still strike comedy gold.

I just think that overall Letterman still has an edginess to him that i really like for some reason whereas Leno I just find boring and not even slightly interesting personality wise.

And of course Letterman is also a much better interviewer and often succeds in getting the best out of his guests.