Don't feel bad about price shoppers
The fact is that a lot of us (men as well as women) really don't know how to judge a craftsman (plumber, electrician, handyman, etc). I say that from experience and lots of discussions with coworkers, friends, relatives, etc.
Ok, so I'm a woman, and I was brought to be one of those helpless female types. However, I've had to learn a bit of this-n-that along the way. Unfortunately, I have yet to find out how to find a good & honest plumber (or electrician for that matter).
I know that I've read & been told to ask friends, colleagues, etc. But the fact is that the guys I know (accountants, businessmen, etc) for the most part don't really have a better idea than I do. My experiences with their recommendations have been less successful than just picking someone at random out of the yellow pages - sad but true.
So maybe you should consider that when someone calls you for price shopping, you really should suggest that instead of just getting a price, they give some of your customers a call, then give them a prepared list of 5 or 6 customers. Most of us don't really know how or what to ask, so if you could point us in the right direction, we'd be grateful and in a better position to compare your service and attitude to someone else.
By the way, I'm an accountant. I would have to say that work from different accountants, CPA's, and tax preparers vary a lot. Yet people just ask about our prices, too. It's very hard to differentiate our services, which are hard for the non-accountant to compare - just the same as for a plumber or electrician, or any other professional.