Assuming this is for CS or some other type of engineering, see if you can find out who recruits at both schools (who shows up at job fairs, who sponsors engineering expo, etc). When I worked at Xanga we visited UMich to recruit but we didn't go to WashU. Smaller places with a limited recruiting budget will probably recruit at larger schools simply because they're better known and you can talk to more people while you're there.

(This assumes that you have an interest in getting a job when you graduate.)