I like to rear my own queens that are 'locally adapted' and occasionally bring in new genetics in the form of queen cells, virgin queens donated by like-minded beekeeping friends & mentors, who keep good bees. Tend to have dark bees & I try to keep to this i.e. select from these rather than keep yellow queens that emerge.
I'm fairly early on in my queen raising experience but have learnt the following points over the last 3 seasons:
-Raising your own is challenging but interesting & exciting & you learn a lot along the way about bee behaviour, makes it very rewarding to do
-Need a place to rear queens where mating success is good (I live at 1000ft in Yorkshire but my 'mating' site is now down in the valley at 300ft. Good diversity and good mating success)
-Avoid areas (if you can) where fellow beekeepers have completely different philosophies (eg at home my first black queen, turned to yellow within 2 generations & became more susceptible to sac brood (my nearest neighbour buys in Buckfast from Devon!)
-Decide on what's important to you & rate your colonies on these attributes. Mine are good temper & calm on comb; reasonably productive (good honey, frugal on stores), relatively free of disease, e.g. chalk brood, sac brood, lower end of varroa numbers, come out of winter on a relatively clean floor ie show some form of hygienic behaviour
-Keep good records & divide your colonies into groups based on the criteria that are important to you & based on analysis of your records at the end of the season . My groups are A) Your best that you want to rear from (2 out of my 12 colonies). I put extra drone comb in these colonies & make nucs from these. I keep the original queen for as long as possible if her daughter queens show similar traits; B) Ok but not sure, need more time to assess. I keep as these production colonies. Don't queen rear from these but I might let them re-queen if still assessing, I also use these to help other colonies out e.g. share brood when needed or use to draw comb if they're a good comb builder (7 out of my 12 colonies); C) Ditch, re-queen (3 of my 12 colonies next year) - usually due to poorer temper or pest/disease weakness e.g. chalbrood, sac brood, high varroa
I am definitely leaning to keeping locally adapted bees & don't think I would buy in from overseas. This is driven by where I live but also I think it's better for biosecurity and the health of our bees in the long run. Raising your own is more challenging but also if you've got 'bee fever' like me, it's very rewarding