MBentz
Enlightened
Streamlight has a better customer service on their warranty. I had an issue once with Streamlight, and they sent me a new light with no questions asked. I had an issue with Surefire, and they had me send in the cracked bezel for proof on a 6P.
I'm not sure your sample size serves to answer which is "best."
If sending in a broken item to SureFire for proof keeps their no questions asked warranty around, I have no issues with it. As is it's fairly easy to go on eBay and see the schmucks taking advantage of the free replacement parts.