Compared to the rest of the Chicagoland market, the Oak Brook region has more expensive rates, and you'll have to negotiate above asking rent to be in this hot region.
In the last 90 days, 68 listings have been listed, so you'll want to check back regularly for new listings. About 1% of the available leases in the Oak Brook are subleases, so you will probably need to sign a longer term lease with the landlord directly. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,500 sqft. Most buildings in this region are approximately 3 floors. Most buildings in this area were built in 1979 and are Class A.