Any addition of landscape support is a positive thing, even if still hit and miss. As of right now, no matter how much I love my HTC Arrive, there is too much of looking at a sideways screen while typing, or being forced to use the onscreen keyboard.
This is the first time I've seen this, anywhere.
Windows Phone 7.5 Mango Landscape Support (Video)
I notice you are in Huntsville. I used to live there about 10 years ago now. Lived there for almost 16 years. I worked on the arsenal with Boeing.