Whoops!
Yeah, I think it came out in March. It uses the XMB style like you said, and you can sync it to the slim. Its pretty damn cool being able to control Blus with it. I know there's a way to shut down the PS3 from the remote, just haven't looked into it yet.
Costco has it on sale for 1700, which is pretty damn good considering Best Buy sells it for 2700 and Sony sells it for 2500.
It's my understanding that the NX is about connectivity, but the HX is all about the picture, while the LX has all the features. I guess the NX and LX can do stuff like YouTube, but mine does Netflix and that's good enough.