Microsoft really did a nice job with their new mobile UI. As Gizmodo says in their write-up, “The result is a feat no phone has performed before: Making the iPhone’s interface feel staid.”

I wonder if this much glossiness and uniformity throughout a mobile OS — everything’s big fonts, big photos, big squares — while nice the first time you see it, actually causes interface fatigue after a while: do you just get bored of the look, as nice as it is? I feel like I was by the end of this video. This is clearly based off the Zune’s UI, so it would be interesting to find out if Zune users (if you can find them) have gotten tired of the design. One of the things Apple does well is to have consistency while allowing its different core OS apps to each have its own whimsical, playful look, for better or for worse — as silly as the font is in the iPhone’s Notepad, and as corny as the calendar app looks on the iPad, it’s fun to open up Weather on an iPhone, for instance, and have it feel very different than Mail or the Calendar. Variety is a good thing.

My favorite bit of this video, though, is the emoticons keyboard at 1:12 in the video. Nice touch: I was hoping someone would do this.

On a related note, the most exciting mobile UI I’ve seen so far this week is SlideScreen. I’ve installed it on my Nexus One, and while I don’t think it’s user-friendly enough to replace the home screen for most people — there’s a bit of a learning curve, and most of the type is just too damn small — it’s gorgeous, very useful, and a great example of how you can completely rethink and move away from the iPhone’s UI.