Russell-
As I stated, this can be debated over and over as everyone has their opinion. If you know all of your specs and not just your span, you would be able to get as close to the same service than going with your local shop. Watching someone live for a few shots is going to help the pro shop operator suggest what as well as think they know your game from that? Most people already know what ball they are looking for for the conditions they will encounter. Most online shops that I know of will contact you, discuss what you are looking for, make suggestions for drilling and also may suggest something different based on this. Local conditions? with the way centers are now, the 'local condition' can be different on a daily basis. If the online shops were doing the same job they wouldn't be so cheap? Again, just because their prices are less doesn't mean they aren't doing the same job.
I know you are not bashing them at all. And it does sound like I am bashing local pro shops. I can accept that mainly because of 2 things. Cost & Warranty. If I get a ball directly from a manufacturer, I go to a local shop, you are looking between $75-$95 in drilling a blank ball with grips. Basically, this forces you into buying the ball directly from the pro shop because after you look at the cost of drilling and the cost of the ball from the manufacturer, you will break even or pay more depending on the ball. What I mean by this is if I buy a Vivid, the cost will be about the same. It may save me $5. If I buy a Frantic, I would be paying more. If you pay an arm and a leg for drilling and say you have a cracking issue(around the drilling), the shops will tell you sorry, we can't help you. you didn't buy the ball from us. Or, we can plug it for you and charge you to fix it.