After studying lots, and doing this for a few years, I think "good management practices" will trump "breed" most of the time. In our cold area, some say Carni, some say Italian, and both can be successful in a cold climate if managed right. I am told the key to raising italians in this climate is big hives (like 3 deeps for overwintering), but it can be done and they can be prolific honey producers in the cold Northern climates. My Carni's all came through the first winter with flying colors and produced lots of honey. This winter they looked great, had lots of honey stores, but all died....go figure. Ya...the feral swarm I caught died first because it's queen failed...
The way I see it, where the bees in the package come from is almost irrelevant...they will all die in 3-6 weeks and be replaced with the queen's offspring, so the better question is what genetics does your queen have? The bees and queens often don't come from the same place and you can buy queens from nearly anywhere in the US for $25-35 shipped. If any particular queen breeder had the magic queens, I would think we would be talking about it on this site. Some will work, some won't, and some that work for another person, will not work for you. The key is to develop management practices that work for you with your bees, in your area, then repeat that process.