They're all good for making me fall asleep. I never find out who the murderer is (too busy snoozing), except for Columbo who tells you right away and then disects it.
I did like how annoying columbo became to the suspects, I also like his dishevelled appearance, but essentially I find poirot boring, sherlock has that drug habit that makes him a little seedy, poirot is just overly polite and a little up himself.