This year I had Italians, Carniolans (which I gave to my brother), Russia, & Minnesota Hygenic in my apiary.
The Minnesota Hygenic were by far the hotest bees in the yard.
Of the different strains the Italians were pretty much what I expected, a good calm productive bee. The Carrniolans were quicker to build up, very calm, but didn't hit the high production of the Italian, it's a nice bee to have. The Russians are very calm, even calmer than the Carniolans, seemed to sustain work at a higher rate the the Carniolans but not as much as the Italians. The Minnesota Hygenics quickly superceded the queen, did wierd things in comb building (They were the only bees on foundation and I had to keep tearing it out and making them do it over), where hot on good days and hotter on so-so days, and I had to force them into a 2nd box.
My analysis, though limited to 1 year of comparrison, is that if you what high honey yield--go with the tried and true Italians--this is a bee you can never go wrong having. The Carniolans and Russians were pretty much a toss-up though I developed a personal favorite slanted towards the Russians. Both are good bee, the best choice if you are in an area where temperment might be the deciding factor, and when not experiencing a dearth should produce a reasonable harvest. The Minnesota Hygenics I found tempermental and contrary, these bees take a little work and are not 1 I would recommend to the 1st year beekeeper.
That's my accessment, make your own decission.