Champion radiators, aka the China made leaker. The quality of the two isnt really comparable, hence the price difference. I havent seen Champion products being used on 6 second GTRs, Porsche cup cars, Trophy trucks, KOH crawlers, etc, but I do see CSF products being trusted on those vehicles. What I do see from champion is 100s of forum threads across all makes complaining of leaking and fitment issues. I am sure some people on this forum use them with good results, but again the build quality is lacking.

You get what you pay for, and if reliability is a concern I think most people would willingly spend the extra money. I run a CSF on my race car, because its mounted above my head and Id prefer not to get sprayed with coolant after bouncing around offroad for 10 hours at a time.