To me he was 5x worse than Harris. I was generally a Gore fan but the Lieberman decision was absolutely horrible. Dick Cheney is a snarling, charisma-less asshole and Lieberman flat lost a debate to him, badly, then decided he did awesome and needed to run for President himself.
As far as being glad, I keep a high bar for celebrating deaths but the fucker was still heavily involved in "No Labels." There's actual tangible good in him exiting the political scene.