Yes, I agree that kudos count is the most reliable. But I'm not sure how it relates to the number of chapters? Like, out of two fics with 500 kudos, I wouldn't think the one with less chapters is more popular/better.

What I find useful is kudos/hits ratio, which shows how many people who loaded the fic liked it. It's also a flawed system, especially for chaptered fics (which usually get more hits as they're updated), but I like it for newer fics and oneshots. Probably not the most useful for diving into a fandom, though :(