The main reason we're even sending Kavi to pre-school (I didn't start school 'til kindergarten myself) is so she'll a) be less bored, b) get more socializing with other kids, c) run around more (she's a little behind in her gross motor skills, I think 'cause she doesn't get enough physical play), and d) get used to the school routine. We're home so much of the time interacting with her, and we tend to default to teaching her things in our play just because we're both teachers. She knows her colors, numbers, and alphabet already -- what more does she need for kindergarten?
If you think it's worth paying more for the fancier places, let me know why?
8:00 - Added to note that she'll definitely be going into public school starting in kindergarten -- that's why we moved to Oak Park mostly, for the excellent public schools here. (Also, rambly old Victorian houses with garden-able yards that we could afford and that were still a decent commute from work.) So while the dual-language pre-schools are definitely cool (we have both Chinese immersion and Spanish immersion available here), if she's going to stop that after a year, I'm not sure how useful it will be. Now, if there were Tamil immersion...
Also, I really like the mixed-economic-class nature of the less expensive schools. Our kids are already going to grow up in a crazy big house, and may even inherit a bit of money from their grandparents someday. (Not from their parents, since we're putting all our money into the crazy big house.) And Oak Park is kind of ritzy. We don't want them to grow up feeling all entitled and such -- money is lovely to have, but my dad came into this country with $200, a promise of a job, and a wife and toddler to provide for. We don't want our kids to grow up thinking they're somehow better than the working class kids in the next town south. Especially since odds are that they're going to be smarty-pants and will have enough ego from that as it is.