He was only funny relative to Leno, but even that wasn't a huge difference. In the 90s and early 2000s, Conan was orders of magnitude better than both, but came on later. One of the real oddities in the history of TVHe was never funny. Popular yes. Funny-no.
Never was a fan but never watched again adter he made the birth of a child with Downs Syndrone a joke and viciously attacked the mother and grandmother. Most liberals loved him for it but regardless, it showed his classless nature. He is just an asshole.