Just for anyone else which was disappointed that the Nvidia driver-level SSAO for GW2 is barely noticeable, introduces glitches and has quite the performance hit. Using NV-Inspector, you can change the Ambient-Occlusion compatibility-bit in GW2's profile to those of:
Darksiders 2 (good performance, good looking soft-AO, this is the one I'm using)
TES5: Skyrim (middle of the road, somewhat darker AO)
Demigod (High performance cost, very nice and very dark)
And probably more!
They work perfect, GW2 with SSAO looks great, and this does not have the transparency-related glitches which GW2's AO profile has, and all are much more noticable and better looking. The only minor problem with it, is that its rendered above the UI and does not play nice with fog, however, it is barely noticeable and does not really bother me. Mind that AO only works if you're using Native-sampling, since driver-level SSAO can not be forced when the resolution of the framebuffer is not equal to output resolution.
I recommend setting AO-quality to "Quality".
HexiumVII, I'm personally using 1.2x OGSSAA (using Nvidia's resolution-downscale method) and SMAA Injector. It looks fabulous. Aliasing and pixelcrawling is completely gone.
Just remember to disable any AA-flags you put in NV-I, and disable ingame FXAA, its implementation by ArenaNet is a terrible, blurry mess.