Just to add some perspective here, I agree the Traxxas prices are salty, however I'm of the opinion that it all comes down to parts support. I've never had any problem getting parts for any Traxxas. Some occasional issues with HPI (and I prefer the way HPI are built, for what its worth). I would be more concerned going further off-piste though.
Back in December I bought a secondhand 2wd Slash for £70 on this forum . Cost another £12 for a full set of bearings, and some enjoyable bench time doing a complete rebuild on it. I then junked the brushed motor and stuck a £50 trackstar brushless combo in it. Now it's fast enough for bashing and plenty of fun, plus it's reliable. I dont need to worry about it skidding 40 feet on the body shell, unlike if I bought a new one. So far it's broken just one part (bearing carrier) despite my 7yo son driving it and planting it into various obstacles at 30mph. What gets broke will be replaced with RPM equivalent. Total cost for a 2wd brushless around £130. Granted, buying s/h from ebay would be much more of a lottery. I see similar RCs going for this type of money on here though and would not hesitate if I was in the market.
Parts support is everything in my book.