I could blather about all the new features and improvements, but this video says it all:
SkyMaxx Pro is an integration of our SilverLining clouds into the X-Plane flight simulator. For more details and to join the discussion, check out the official SkyMaxx Pro 3 announcement on X-Pilot.com. SkyMaxx Pro is already the most popular add-on for X-Plane. With new stratiform clouds, extended draw distances, and lots of extra polish – it’s about to get even better!