I'm facing a similar dilemma, too.. the more so because I'm flying from overseas. If I had more choices, I would like to have the chance to visit as many schools as possible while I'm in the US, but so far I've only got one Open House invite, and it seems like most of the other schools I applied to have already sent out their acceptances/open house invites. Oh well..
Does anybody know if UChicago has sent out all the admission offers already? I only see two UChicago posts so far, so I'm still holding on to this little bit of hope...