For me he fits into perfectly into the category of "villains I find sympathetic/endearing but not in a way that excuses their villainous actions which leads to strangely enjoyable emotional conflict about how I love them but they must be destroyed".

Also the fact that he's Han and Leia's son, while it makes his actions that much worse, also means I just WANT to love him so bad and want him to come back to the Light Side because he's HAN AND LEIA'S SON, he can't be beyond redemption.

Aaaaaaand everything about the way Adam Driver plays him just works SO WELL for me, I would watch him alternately cry and menace people and then try to menace people but it doesn't work that well because he looks like he's about to cry forever.