Xray, Tamiya, Schumacher....have raced them all. All are great kits and out of the box will do the job for most drivers with the chance to upgrade as the skill level increases.

My suggestion would be consider the brands the racers are using at the track you race, what brand works well at the tracks you race at (as a yokomo doesn't work as well at my track as schumacher does as it's low traction) and along with local support and your budget that should provide some guidance to the make of car that suits your needs.

Others have suggested brands racers are using, and this can't be discounted as sharing of set-ups and parts when needed can be very handy in a pinch.