I don't think there's any ONE best breeder, outside of Mr. Nice. That would probably be due to the fact that it's owned by Shantibaba, the man is just pure genius, and was a participant in the creation or the creator of quite a great number of the sought-after classics. White Widow is one of his. After the flap with Greenhouse seeds, he re-named it Black Widow and that's what he sells it under now. If you look at the website for his seedbank, you can find out all you need to know about his strains. The man is just simply a legend.
Aside from that, you should browse through the smoke reports and seedbank reviews and use the hell out of that search feature. That'll be your best bet. Otherwise, you are going to get a boatload of conflicting, possibly even argumentative information. These reviews have actually got me considering strains that I originally had no interest in.