The Microsoft Garage has given birth to a myriad of interesting apps with limited utility, but everyone needs a home screen, right? Microsoft made Arrow Launcher available as a beta over the summer, but now it's available in the Play Store for everyone to try. It'll take some getting used to, though. This isn't just another AOSP re-skin.
Arrow consists of several different pages (nothing new), but each of them has a specific purpose. There's a smart app list that changes as you use it more, top contacts, recent files/apps, and optional panels for widgets and quick notes. You can set any of these as your default screen and rearrange them as needed. There's also a nifty dock at the bottom that has quick toggles and additional app shortcuts.
As we mentioned when the beta was released, Arrow has a similar feel to Aviate. However, it doesn't seem unnecessarily packed with Microsoft services in the way Aviate is with Yahoo stuff. The only Microsoft integration I see is the automatic background pulled from Bing.