S.
A little advice from another Realtor...1st, I also suggest checking out greatschools.net, but also check out the Illinois State Board of Educations report cards for the West Chicago district, this site will give you demographic information as well as test scores. You can search by district as a whole or by individual school. I can't speak from experience, but I can tell you the district doesn't have the greatest reputation.
Second consideration is that not all of Winfield goes to West Chicago schools, the east side attends Wheaton's district 200 schools, which is an excellent district.
Finally, someone asked a very similar question a few weeks back, so you may want to do a search on this board to read some additional responses.