Pros
There's some decent restaurants nearby for getting some lunch from, which helps because otherwise you will likely get pestered to work while eating lunch. The coffee is decent. If you live near the blue line it's an easy commute.
Cons
The company culture is toxic. The CEO frequently makes it known that it's "his" company and will involve himself in decisions he knows next-to-nothing about. The company outings are a joke and incredibly forced and awkward. Since it's a small company you feel like you have to go because it will be noticed. The software is just a giant ball of bandaids. There is no real project planning and anything that gets done is done as quick as possible to satisfy a promise already made to a client. The pay is a joke, they pay on average at least 30% under median for Chicago. The only people that make any decent money there is the CEO and the VPs, who are his friends/family.