World Heroes 2
You asked for my favorite with no BS. It's a combination of genuinely liking the game and nostalgia. I remember watching it in arcades as a kid, and it was the first Neo game I bought. As a guy who doesn't take anything too seriously, I like it for its cartoony art style, goofy characters, funny moves and stupid back to the future rip-off plot.
There's tons of other fighting games I own that I know are better, but I'm not a serious player in any fighting game and I don't have much competition to play against. Thus, things that most people care about (balance and all that jazz) fly over my head.