I'm an occasional NYC visitor and love the AMPs.
I'm seeing more of these tagging the girls as GFE, and yet it's not clear to me what this is doing to the service and price structure.
Is this usually an option so you can ask for GFE or non-GFE? And is there a standard rate? Any info helpful, feel free to PM.

If we're talking about the same 10-20 AMPs with the same ad formats ("New!" "First time in NY", "GFE"), then, even if a girl has "GFE" on her picture it is just an option.  You'll figure it out once you're in the door.  If you start with non-GFE, you can still go for an upgrade during the prelims (table shower, massage).  

The upgrade varies from +1 to +1.5.  The definition of GFE varies from individual to individual, so you might have to 'gently' ask for details: BBBJ is usual; MSOG is common; but YMMV.  

There might be a girl or two who will only do GFE and not accept non-GFE clients but I've never come across that, myself.  Just sayin' ..