rae21 - A question you should answer for yourself is "What am I looking for in a hitting coach?" Sit down and make a list of the things that are important to YOU. Ask questions!! Don't just take anyone's word as gospel, because everyone has different goals and expectations. Just because someone is (or was) a college coach, player, etc. doesn't automatically qualify them as a great teacher. They might be, but that's a very subjective issue.
You MUST define your expectations. A few years ago I quit taking my DD to a certain pitching coach, NOT because he wasn't a "nice" guy (he was, and still is), but my DD WAS NOT advancing her skills at a rate that met our expectations. We switched instructors, and she took off again. The first guy has lots of students, but things didn't click with my DD.
We must get beyond the mindset that "If they're a college coach, then GEE - they must be a good instructor!" I got news for ya - college coaches get fired every year for non-performance. I'm betting every concrete truck driver doesn't know how to build forms and finish out a driveway. The astronauts that walked on the moon were taught by people that had only seen the moon through a telescope!
Find out some stuff about hitting ON YOUR OWN - it's all over the internet. Make your decision based on what you want you kid to be taught. I'm not going to go into detail, but there is a LOT of bogus teaching out there. The more you find out what works and what doesn't the better off your DD will be.