I came to Chicago for PokemonGo Fest and had a great time staying here. This place is in a prime location - very close to many local attractions, including Millennium Park (be a tourist and take a photo next to the donut), Navy Pier, many museums, and great food. Depending on what you plan on doing, you probably won't need a car - you'll be right next to multiple public transportation options with a quick direct route to and from O'Hare.
If I ever need to come to Chicago again, I'll likely stay here again :)