I'm one of the guys who got the phone two days ago. You can read my quick review here.
To summarize: the user interface based on swiping works quite nicely, even if a bit confusing at first, and the phone works OK as a minimalistic smartphone. On Day 1, there still are quite many bugs and usability issues that need to be worked out.
Compared to Android or iOS, the visual simplicity of the user interface views is extreme, no buttons or decorations almost anywhere. When you open the phone app, you just see a very plain call log. In the email app, you just get a list of emails, and when you open an email, there's just a title followed by text. On the downside, views are often rather over-simplified, so that things are hidden too well, and workflows to get to what you want are often a bit complex and unintuitive. There's no status row that is always visible, system settings aren't accessible immediately everywhere, but you need to go to the start screen, etc.
Some critical features such as WiFi access point missing (or I just haven't found it after poking around 2 days).
Around 30 native apps; some Android apps work just fine, but many do not, and the selection is in practice very limited.