For a long time I've been debating with myself whether to get SkyMaxx or not.

I finally decided to pull the trigger so here are my first impressions together with some screenshots (click for larger version, click again for even larger version)

 

These are the settings I've settled on for now

 

And these are my X-Plane settings

 

 

First from the ground, with a low cloud layer starting at around 4,500 feet, except for the cirrus shots which had the layer at 30,000 ft

 

Clear skies, 46 FPS (for reference):

 

 

Default clouds:

Few:

 

Scattered

 

Broken

 

Overcast

 

Stratus

 

Cirrus

 

Now with SkyMaxx Pro v2.1

Few:

 

Scattered:

 

Broken

 

Overcast

 

Stratus

 

Cirrus

 

Medium altitude, default:

Broken

 

Overcast

 

Medium altitude, SkyMaxx:

 

Broken

 

Overcast

 

 

High altitude (Overcast only)

 

Default

 

SkyMaxx

 

The default clouds look decent when using a broken or scattered layer. With “few” clouds, by default you just get a few odd looking wisps of clouds, where as SkyMaxx gives you proper puffy clouds. The FPS is also generally better with SkyMaxx, and you can have denser cloud coverage before the FPS starts taking a hit.

 

The big weakness of SkyMaxx is overcast, especially from the air. It doesn't look great, cloud coverage ends abruptly even if you max out the draw distance. FPS is on par with, or worse than the default clouds. SkyMaxx does offer three options for overcast:

Low: Just a 2D texture layer, extremely FPS friendly. Not pretty, but functional

Medium: Looks more like a broken layer than overcast, quite FPS friendly

High: Proper, 3D overcast layer, but big FPS hit

 

 

Cloud shadows look great, more defined than default X-Plane. One thing I noticed is that the shadow intensity does not fade with distance/haze, so distant shadows really stick out. This can be worked around by dialing back on the shadow intensity and cloud draw distance.

 

Crepuscular rays look great under the right conditions. There's a noticeable FPS impact from enabling them, but only when they're actually visible. I leave them enabled because they're so pretty.

 

Conclusion: For the VFR pilot, SkyMaxx is a win. It allows you to fly with scattered/broken clouds at a (sometimes much) higher FPS than default clouds, while also providing much better graphics quality. For IFR pilots, you may want to stick with the default clouds, which at IFR conditions provide better coverage at a lower FPS hit. Of course every system is different, so your experience might be completely different.

Thanks for the time you took to post screenshots.  I just installed SkyMaxx and UrbanMaxx and haven't played much with the settings, but on a flight today up the east coast of the U.S., clouds were very realistic and appropriate.  I always fly with "real weather" so I haven't encountered overcast conditions yet.  And like you, I have a lot of horsepower to play with when pushing effects.  Slower machines may require some compensation in other rendering settings, but I didn't notice any problem with framerates.