I agree with Ryan and wmburns. I like the default x-plane weather, because the reported levels are spot on accurate. I disabled Skymaxx because getting accurate cloud levels is more important than the cloud textures, and as far as I'm concerned, the texture and cloud realism of the X-plane default is pretty good. The only oddity is the occasional insta-grayouts where you go from seeing clear and a million to zero vis in a second once you enter the layer or METAR area that's reporting that particular ceiling and vis.
The one software plug-in that I absolutely love is g2xpl. It's free with a donation, but the donation can be as small as one euro if you're a cheapskate.

It takes a while to download the photo imagery data (which is free) depending on the zoom level you choose, but what an improvement in the view and situational awareness if you are flying VFR over familiar territory. Huge improvement over the default X-plane scenery, which in many areas isn't all that realistic and can be very repetitive. If you go crazy with it, you'll need a good size hard drive. I'm working on filling 3 TB at zoom level 17 . . . for now, but you could do ZLA in about 400GB at that zoom level, or back off to zoom level 16 for one-eighth of that ~50GB.