Whichever is cheaper. When it all comes down to it they're both the same exact toy. If the tires split, glue them. Very easy.
Car Robots is less prone. The only Car Robots item I own is Black Convoy, and I love him. I'd have been happy with Scourge too. Basically it is just which one you prefer.
I only owned the Hasbro Version and it worked pretty good for me. However, i'd go with the cheapest also