Well, let's break it out by things you care about:
1) Community: Kellogg wins this for sure. Almost everyone lives together on campus 45 minutes away from Chicago so you really have a community that sticks together in Evanston. Columbia people are more spread out. I don't think this is a bad thing, but it Kellogg has that undergrad type vibe when it comes to its community.
2) Fiance: You have to determine how much this matters to you. I will say, one thing that turns people off about CBS is the COL. But if you are splitting a 1 bedroom with another person you can save and bring that down to more in line with other schools. Though you have that large scholarship from Kellogg, so it definitely won't ever equal.
3) Midwest vs East Coast: This isn't a huge deal. You can recruit well for most industries on the coasts from Kellogg. CBS does get a lot more on Campus interests from smaller banks, funds, asset managers, etc that are based in NYC. Which brings me to my next point:
4) If you want to do AM, CBS blows Kellogg out of the water. The Value Investing program combined with all the midsize and small funds, shops, etc that come on campus that don't at places like Kellogg makes it as good of a school as there is for AM recruiting. That said, a lot of that recruiting is determined by your pre-MBA WE. So if you have a non finance background, I wouldn't expect to get interviewed by Fidelity or Wellington anyways. As far as consulting goes, CBS has very good consulting placement too, but Kellogg kills consulting. So if you are leaning that way Kellogg has an edge there. As for the others it's a bit of a wash.
I would say, with the money differential, Kellogg should be the choice unless you absolutely know without a doubt AM is for you, in which case CBS is worth the extra money. And no one can tell you how much it matters to you to be away from your fiance, so you'll need to weigh that, as well.
Also, go to the admitted students weekends. See how you fit in with the communities. That may ease your mind a bit.