If you buy a XB (Xpert Built) car, you should not have high expectations. Just because they are built by experts (can someone define what makes someone an expert builder?), it does not mean that they are top notch cars. In fact, the XB Desert Gator and the XB Sand Viper are just Super Fighter G kits, put together by so called experts and sold together with radio gear and Desert Gator or Sand Viper body and wheel set, nothing more, nothing less, they do not even have ball bearings.
Don't let this lines fool you, I do not think that the XBs are junk or something, I just want to say that you should not be fooled by them. They are not better than a standard kit with electronics, that's all. But if you are short on building time or you are not able to build a car (whatever be the reason for this), then these are for you. For all others I recommend to buy the kit and some decent electronics, it is cheaper and for me building a car is the same fun as driving it.
The XB Desert Gator is a good basher, especially when it gets wet, because the body is shaped like the baththub chassis underneath it and so it keeps much dirt and water out of the chassis. To make this perfect, you can use velcro tape to fix the body to the chassis, then you can forget about the nasty clamps and body pins also.
If you want to go racing, then you can upgrade the car with all the goodies you can use on Super Fighter G, Desert Gator, Sand Viper and DT-02 MS.