So I went with the Maisto. Its a good choice for a 4 year old. He played with it for the first time today (it was contingent on getting a workbook for school done) and really liked it. He has like zero hand-eye coordination for something like this so it will be a learning curve.
I didn't realize this but, the throttle is just rev/off/fwd, there is no part-throttle. There is also no part-steering. Its full lock or nothing. That said, full lock still has the turning circle of a Miata, so I don't know why you would ever want less than that anyway haha. None of that is a dealbreaker right now, but I could see others being disappointed if they weren't aware of it.