I can't tell for sure, but I
think that
REX Essential PLUS HD with OverDrive may be slightly updated.
If it's close to what I bought back in 2013 you might want to buy it
just for the textures. And there ARE a lot of textures, not just cloud textures.


You end up getting a large number of choices for everything, even the coral around Pacific islands.
The one thing that I DO NOT like, is the weather engine. But you don't have to use the REX weather engine every time you fly.
You can just pick the settings that you want for multiple thousands of environmental combinations. Once selected it's saved into
FS9,
FSX, or
Prepar3d.
All in all, I use the REX textures with the OpusFSI weather engine.
But you can use absolutely any weather, or none, it doesn't matter - when you save your texture selection it becomes a part of your flight sim files.