I would be very happy with a two position switch to turn the car off and on and a push button starter. All the single button systems have design issues.
Ah, someone else who has experienced the issue I have. The core problem with single button systems is they try to represent 3-4 states (depends on if you count cranking as a state), but a single button can generally only transition from one state to another, so is best suited for 2 states. So you get weird hacks like leave the shifter in neutral if you want to go from running->accessory, and then press the button twice to go from accessory->off, or having to hold the brake while pushing the button to start. I like being able to leave the key in my pocket, but a knob or multiple buttons seem like a better system than the single button most have now. I suspect Nissan is figuring this out; they had a single button several years ago; last year my parents looked at one and they've went to a knob in the place where the key used to go.