I've been in Chicago for business for the last week and I haven't had many problems with cabs.

One problem I have had (and I might have this everywhere) is that they cheat you when you're from out of town. For instance:

Last night heading from my hotel near the Hancock Building to a restaurant on the Westside (outside of the loop) near the L....

Getting there: $15
Getting back: $11

Hmm....someone took the long way.....

The second, is the credit card issue. I don't like carrying cash and I know that cabbies have to take it. So if I know the cab ride should be $10 or more I ask them if their machine is working. If they say no I wait until the next cab comes by. If they say yes, but "suddenly" it malfunctions at the destination I give them the option of figuring out how to make it work or having just given me a free ride....Amazing how quickly they get the machine working again....