Mostly an improvement
The only problem I have with it so far is that the excellent "Inside Xbox" from the old version hasn't translated well to the NXE. The simplicity of a little orange icon that tells you there's new stuff to read seems like a better option than a massive coverflow of confusing images and truncated text.
Also the recent additions to the marketplaxce seem slower to navigate. As a result I'm finding it a lot slower to check up on the recent additions to live. Given that the whole aim of the NXE was to make the dashboard more of a place to explore what you can do with your console I find that surprising.
Maybe I just need to get used to it. Only time will tell.