I went to a conference in Chicago this past summer. The conference was good, but the pinball was better. I was there three nights and got to hit up all three... Emporium on night 1, Logan's on night 2, and Headquarters on night 3. Here's my quick review:

Emporium - more than just pins... lots of arcades, too. Darker atmosphere, as mentioned before, but that was also because I was there until midnight. Fairly priced games. I preferred this location/layout.

Logan's - was underwhelmed when I first walked in, but realized there are two back rooms... one for arcades and one for pins. Again, darker atmosphere, but a good variety of games... both new and olde.

Headquarters - free games. Yes, free games. But, here's the issue... people walk up, start a game, lose their ball, and walk away. So, you end up draining two balls just to start a fresh new game. Also, issues are impossible to find out ahead of time because a ball might get stuck and they walk away. But, free games were nice. When I was there, WOZ was available for $1/play, but the new Mustang was free.

I would imagine Headquarters is going to be your only option; the other two don't really have any separation between their bar area and their game area.