I too really enjoy the iterative changes in Android 4.2. There are a few things that I would have preferred for the stock experience, but these have more to do with the default apps, minor UI tweaks, and certain default OS settings. But these are mere nitpicks, as the experience is quite good overall.

The OS itself, seems to run very well, and the changes to the UI are very welcome. I'm looking forward to the Nexus 10 (as a shareable tablet, and a mobile development device), and the oh-so-gorgeous Nexus 4. I'm interested in noting the differences in performance that the various SoCs offer -- something tells me that the Exynos 5250 will perform extremely well with excellent SSD performance and best-in-class single-thread CPU performance.

As a developer, I'm very excited by the new APIs. One of the most understated features is Renderscipt Compute on the GPU that is now available for (presumably) the Nexus 10 and the Nexus 4. This should allow for complex things like image processing and video processing to be done at desktop performance, and hopefully some forward thinking developers take advantage of this powerful tool!

I also think Daydream is a really great new feature that hasn't gotten a lot of press. People see it as a screen saver, but any app can display any content when the daydream is triggered. It can act as a night-table clock, a news ticker, a security cam, etc. And daydreams are supplied like widgets, they come packaged with an app, so installation is really straight forward.

Lastly Mircast wireless display is perfect. It's not just about mirroring -- Android can actually display different content to the wireless display! This means a smartphone with video content could display a remote on its screen, while video is being streamed to the TV. I can think of some neat multi-window setups using this technology.

I'm really excited about the the next verision of Android. I think we'll see OpenGLES 3 which should bring the graphics API much closer to the desktop as well as more neat user-facing features. I really hope that multi-pane finally makes it to the platform and not in the ridiculous way that Win8 implements it.