The 4pv is the new mid range futaba, 4px is the high end. The 4pv has the same latency as a high end spektrum, so it's a good option to save some coin. I went from a 4pl (there mid range at the time) to a 4pksr and don't notice any difference beyond some of the features I now need and use (for combat robots mixing, the 4pl was more then enough when racing) so yes, even the 3pv is a very valid option for racing. I don't think you'll ever find a need for anything more then the 4pv unless you're doing something more then racing that may need some of the odd features of the 4px, but the high end radios are really cool