As someone said before, if you can swing the extra cash for the Team Magic G4S RTR it's a much better car than any other RTR. It's also the easiest car to make into a competitive racer. You can upgrade the parts to the Kit version piece by piece and basically have the Pro kit version of the G4S. The only caveat is that you need to buy a starter box for it as the engine that it comes with is an SH .12 with no pull starter or electical starting system.
It goes beyond the ~$300 pricetag you mentioned but I think the car would be worth the extra few bucks for someone who was considering getting into racing in the future. You can evolve the car into a competitive racer over time if you choose. Currently the buggest drawback to this car is that you cannot find it locally in most areas and you will most likely not find parts stocked for it. You will have to go online and order parts and things.