The only problem i have with Open RWYB, is that you get non scale cars running. I would like to keep to scale rally cars. But that means, everybody would have to buy a new ride. But heres the good part. You dont need a Mega Fancy car. A used TC3, or XXXS, or Tamiya car would work. Heck, any 1/10 4WD Touring Car would work. Honestly, you wouldnt need to spend more than $250 for a RTR car.
And Rally Legends offers some mega saweet RTR Cars! They are more money, but you get very nice bodies, LED lights, etc. with em. Well worth the money, and they have a good Hop-Up Selection and Part Support too. Check em out:
http://www.rallylegendsrc.com/