first glimpse of T-Mobile's new 2009 edition Sidekick LX was all too brief, so we've jumped back in for some in-depth video hands-on (embedded after the break). One word of warning: this screen is truly incredible, and we can't be held responsible for any instances of sudden onset Sidekick envy. Traipsing through the OS, we found most everything to be responsive, intuitive and actually pretty feature-packed. The Facebook and Twitter apps are some of the best we've seen, and Laura our demo person was actually brave enough to shoot, upload and stream YouTube live on video with us. The browser had a bit of trouble with the visceral multimedia experience of Engadget.com, but overall seemed fairly together. The Download Catalog is a little barebones at the moment, but promising. Overall the hardware will be totally familiar to Sidekick users, but there are enough enhancements and refinements to make this lust worthy to folks on both sides of the Sidekick fence. It's comfortable in hand, with soft touch plastic and a super solid build, despite our best efforts at wrenching that swivel-and-tilt screen from its magical hinge. The phone hits T-Mobile on May 13th for $199 after rebates.