When Russians were first brought over, it did not take long for southern producers to find out that they were not conducive to what they wanted in a bee. Russians seem to stop in a dearth, overwinter in a smaller cluster, and do not build fast until a flow starts. Large commercial types need bees that brood endlessly, overwinter in large clusters, etc. That's why some large producers started with Russians and then changed back to Italians. And so you heard that Russians were mean, they were aggressive, they produced little honey, and so on. Seems, it may be in their best interest to make sure Russians, and even carni's are not seen as something worthy.
But what may good for large producers may not be good for beekeepers, and northern beekeepers to be specific. I want frugal bees, I want bees that shut down when no nectar is coming in. I want a bee line that may be better at handling increased mite loads. And I think their adaptability is more in line for survival with northern climates.
I actually use Russians and I am really fond of carniolans. When I started culling out my Italians 6 years ago, and went with no treatments, I lost 60%. I have culled out most Italians and now have a hybrid Russian and carni line that last year lost 16% with NO treatments. I can not say I could of accomplished that without the Russians and carni lines. And I also will not say that it was entirely due to the strain of bee, but other management and IPM played into it. But starting with a good stock and building upon the advantages they give you, is a good way to go.
Which takes me to the next point.....Many people market and sell bees on a "label". A breeder and a person to consider getting bees from should be more than a person who orders a fresh standard breeder queen every year and sells first generation daughters. A breeder should be perpetuating a line tailored to your requirements. And no breeder can select for everything. Ask questions, and get to know your options. Perhaps instead of asking about Russians in general terms, asking who breeds good Russians, and what traits are they known for, is a good way to go. A breeder may have much more to do with quality and traits you want, than what type breeder queen they started with.