this is what I had when I was 4:
Believe it or not, it was a ton of fun and I actually wore one out over the couple years and my parents had to get me a new one. Thousands of laps around my house . . . . . I guess that's why my carpet is so flat now.
As far as the Evader BX - a 4 year old will break it, trust me. Regardless if the parts are free for one year, it will have more down time than runtime.
My vote: XL5 Bandit, with training mode enabled to limit the throttle to 50%