The advantage of getting instruction from an established shop is there may be more insurance available should something go horribly wrong.
If you're down to that particular selling point, it might be time to roll up the carpet and look for something else to do for a while.
Well, I don't understand, but then again, maybe you missed my point.
My point was there are some very good instructors out there. Some work out of shops and some work as independants and that the location does not matter. Maybe I should have said, "One advantage".
I can only speak for NAUI ... but they make no distinction between independents and shop instructors in terms of how much liability insurance ($2 million) you are required to carry. I doubt any other agency that supports independents does either.
Point taken. However, a shop or other business may have additional insurance beyond what is required.
Just so I'm clear, I'm not making an endorsement for shop only instruction as I strongly feel that the instructor him/herself has the single largest impact on my training. Not the agency, shop or gear selection.