Was at MKE on a recent Friday evening and EA had your selection of any car, as long as it was called "PT Cruiser", and ES had your selection of any car, as long as it was called "Impala" or "Malibu". One odd thing was the need to sign some weird Wisconsin-mandated legal form at the gate about car insurance, which just seemed more confusing than anything.
I do like the fact that the rental cars are literally across the street from the terminal, as opposed to other airports (ORD, IAD come to mind which, I acknowledge, are much larger) which require a long wait for a bus and then a long/slow slog to get to the rental location. It was nice to land at 7:22 and be out of the rental car garage at 7:35!