If the question was which game is more significant or influential, that would be easy. FF7 uncontestably beats almost all other JRPGs in such a poll.

But if the question is simply which is a better game, I have to go with Suikoden II. I consider disc 1 of FF7 to be one of the top JRPG experiences, but the game breaks down after that into a haphazard mess story-wise. It's still one of my favorite FFs, but I rag on it a lot because it could have been a lot better. Suikoden II on the other hand is so much more polished and cohesive, as well as with better characters and story (two of my primary concerns in an RPG).

I'd put the music more even, coming squarely between WK and MILF. I think the music overall in S2 is fantastic, but it's very difficult to beat some of FF7's top themes. S2 is one of the best games at fitting music to atmosphere (Reminiscence and Moonlit Night Theme never fail to give me feels), but FF7 has a handful of truly memorable themes that are above and beyond pretty much anything else in the genre (Aerith's theme, Cid's theme, One Winged Angel, etc.).