I own both the 6s and 4s Kraton and Outcast.

The 4s cars have been very durable but then again, I don't push it as hard as the 6s rig. Obviously, the old saying of "you get what you pay for" holds true here. I have all the 6s Arrma's, less the Typhon (I have the 3s version), and I must say they are my GO TO bashers for reliable running. The 4s cars are quick, nimble and thrashable, but I also remember they come with plastic driveshafts and a weaker chassis. 4s is really the limit of that design with that drivetrain, despite it's upgrades over the 3s stuff.

In the end, If I was spending $400 on an RC, I'd save a little longer and spend the extra $150 bucks on a 6s to "futureproof" myself. Besides crawlers...who really wants to upgrade to a slower RC, right?