I recently went to a AMP in NYC and had a great time with a provider who was 4-6 years my senior.  Now I am wondering whether I should see this provider again or try a different girl.  Do you get better service with a provider you have already been with before.  Thanks for the input.

If you enjoyed the session why not see her again?  That way you won't have to worry about the quality of service.

sure, see her again. You may be disappointed with a different girl if her session didn't live up to your first. BTW, consider going to a well reviewed escort outside the AMP scene. I've never gone back to AMPs after becoming a TER VIP member.

I wouldn't hesitate to see a girl the second time or again and again.  In my experiences with AMP girls, if the first session was good, it usually gets better as you repeat.  She gets comfortable with you, knows what to expect from you, learns what you like.  She may begin to offer you things she won't do for others.  She may also be flattered if you select her or request her.  

Variety is good too, but repeats can be better.  You can't expect a GFE first time but I've approached that when repeating several times.

Actually funny that you mention that, I lost "it" to an agency girl who was gorgeous (9.5 out of 10) but the performance left a little to be desired (6-7).  Though hindsight tells me maybe it was my sheer terror and high expectations that made the experience a 6 or 7.  Don't be so quick to dismiss the AMP girls, the ones I've seen were at 7-9 in looks and about the same performance, plus good "bang" for the buck.

Combining the others' replies would be my response. See a couple of other ladies, enjoy the variety, and then go back and repeat with the first one you saw, at a later time. This way you don't get caught up in just seeing one particular lady each and every time. Not that this is a bad thing, but it may be wise to at least explore your options and make sure that she is indeed the one for you.

What I have discovered is that no matter how great I think that first ATF is/was, there is always a different (sometimes better) experience available, and it would be a shame to pass that up in my opinion. Any guy who has been at this for any length of time has probably gone through multiple ATF's.

food for thought, and wish you the best in deciding what is right for you, mr.man