I do not think this is a reason to stop purchasing at NB if they have what you need at the best competitive price. I will keep on buying there almost exclusively as their St Paul store is just a few blocks away from my house, they are my local HBS. Still a great place to buy what I need for me...
I could be wrong in my assessment . But I believe the Minneapolis store opened a few months before the equity firms arrival and the departure of these guys was about 6 months after. Timing is very odd. Adding salespeople really means nothing, as a marketing director's(Keeeler I thing was in this...
Just has been my experience that these firms require large returns for their investments which requires freeing up cash, the easiest way to free up cash is by payroll cuts, especially higher level employees.
My guess would be that it all has something to do with this Private Equity firm from Philadelphia that purchased an undisclosed portion of Northern Brewer, for their "operational experience"