It really depends. I hate to say this but I must be honest here. The USPTA strives to maintain balance in a teaching professional but I have seen some USPTA pros that were pretty bad.
On the other hand, I have seen some USPTA pros that are very very good. To become certified a pro needs to go through several exams.
1. Strokes: We must be able to hit all the strokes with good form.
2. Teaching: We must be able to demonstrate compentance in teaching a group and a private lesson.
3. Stroke Analysis: We must be able to discern a problem area in a persons stroke.
4. Tennis knowledge: We must pass a written exam in different area of tennis; rules, tournament draws, little tennis, tennis strategy, tennis history, etc.
5. Grips: We must be able to tell what grip a person is in and how to easily teach grips and the strengths and weaknesses of each grip.
I cant speak for all testers but in my area the pro who tests us is pretty strict. If you dont pass a test, you have to come back until you do before you're certified. I have heard some testers are less strict. Maybe that is why we have some issues with this.
You have to keep paying yearly dues to remain active in the USPTA. Some pros pass the USPTA test, then after a year they stop paying their dues (which is mainly for insurance) but continue to say they are USPTA Certified based on the past.
Here is a PDF file to learn how to hire a USPTA pro.
http://www.uspta.com/html/How to Hire.pdf.
Now, I dont want to paint a picture of disarray in the USPTA. It is just the opposite. The USPTA is always providing us with courses and ways to learn how to teach and develop players from beginners to pro's. It really depends on the individual pro and if they want to continue learning and improving hier skills for his/her students. Some pros are lazy and never attend classes, others are very diligent.
I would call the guy and find out when he is going to teach lessons, then show up and watch. Listen to what he is saying. Try and be at a lesson that the student he is teaching is about equivalent to your level and see what the pro does.
There are a lot of good pros out there. On the other hand, there are a lot of good pros that are not USPTA certified and handle their insurance themselves. Some don't carry insurance which you should be concerned about. If you get hurt and it was their fault, they need to have insurance. So start with that question.
As far providing pricing on the website - there could be issues with that fro other pros. Does paying $75 to one pro mean he is better than the one charging $50? Or will the pro that charges less get more students then the one who charges more? More phone calls? I dont know. But I bet it has been discussed before.
Dont get me wrong, I hear you about having a central place to look up things, but if a pro found out how much someone else charged for lessons there might be some issues that are outside of this discussion. There could be a good reason why it is not posted.