Umberto - Like many, I'm gradually converting from FSX to P3D, and being able to run a common GSX version on both platforms is superb.
However one wrinkle: I have a dozen or so AES airports installed in FSX (mostly to fix static gates), and had GSX disabled for them using a disable_on_airports list. However since couatladdons.ini is generic to both FSX and P3D, so unfortunately they are also disabled in P3D, and of course there is no AES service there (and no prospect of a P3D AES, possibly due to GSX market dominance ?).
Several others have encountered this problem (e.g.
http://www.fsdreamteam.com/forum/index.php/topic,14476.0.html)
In some future release is it possible to have platform specific GSX .ini file disable variables, e.g. disable_on_airportsFSX and disable_on_airportsP3D ?
Would solve the problem neatly, while preserving the commonality of all other GSX settings across platforms.