I can only post my experience of queen rearing from grafts and from splits for one year. Queen rearing takes a lot of time and resources. I can't see how you would want to make queens, *while confirming they are all well mated* confirm capped brood etc., when you could when you could sell nucs instead. Rarely did I have a situation where I wanted to sell a confirmed mated queen only and not the entire nuc. To confirm my queens mated status I always waited to see new eggs and capped worker brood from those eggs. This takes up valuable time and space in an apiary. I also just left them in the nucs until I sold or needed them so they could keep laying.
I am certain I will buy queens here and there over the years. However the queens I was able to produce on my on, on a small scale, seemed to be larger, better mated, and rearing to go out of the very few that I have bought. The biggest thing you are able to control about your own queens is... culling out the lower third of "dinks". From a queen rearing perspective it would be much easier to just send a queen and replace if it didn't work out.
I am sure there are lots of good queen breeders out there though - I have only enjoyed focused queen rearing for one season.
going with local breeders is a good idea, but part of my management is centered on introducing varied genetics to the area. That means adding in a couple new queens from various locations each year.