i had a very verbal falling out w/ grubhub over their site...
they do have an extensive list of places that deliver to you.. it's probably the best.
the problem is up until recently, they allowed people to anonymously review restaurants on there, and there were some restaurants where it was absolutely clear that there were 10 postings a day from the restaurant owner. so the results were skewed accordingly. i got very pissed off and verbal w/ them about it, because it was so blatantly obvious there was no way they didn't know it was happening (Nan's in Lincoln Park was one of the bigger offenders. they actually went as far as to reuse my very unique name two days after I reviewed them on grubhub)... they've now changed their site to hopefully mitigate this... they tie your review to an actual order, so you actually have to order i guess to review, and maybe they have an account system or something? i don't really know, i haven't looked at it much.. last time i used their site, my order was missed over by them and when I called to inquire why my food wasn't there it was a big "ohhhh, we missed" kind of thing. i don't think that happens very often, though, and there's an automated system they use where the restaurateur is supposed to enter the delivery time into the phone, which then in turn is available information on their site.
i do give them credit though for a few "green" things they do... they have a "no condiments" button you can check so when you order chinese you don't get 100 packets of soy sauce, 20 napkins, 14 fortune cookies, 10 hot mustards, etc.. and they supposedly purchase carbon offset points for every order purchased through their site. (surely this is more symbolic than actually useful, but i guess "every little bit...")