I'd like to thank the Adobe Labs team for making this bold move towards HTML5 and CSS3. I think it's the best news we've had in weeks, and maybe the most important news in 2010 regarding web matters. It even made me totally forget about the Apple vs. Flash debate that's going on and on...
I was already missing the Multiscreen feature as presented earlier, before CS5 officially appeared without it. So I'm glad that it's now available after all.
Please let us know how your experience of using Multi-Screen Preview goes! We are eager to make this be a great value-addition for multi-screen web development.