I have played around a bit with a Lumia some weeks ago (it was available earlier in Europe), and I have to say I was quite disappointed. Microsoft waited too long with screen resolution upgrades, and its low resolution makes it feel like an Android from 2 years ago. That makes it hard to trump modern Androids like the Galaxy Nexus UI-beauty-wise. The navigation paradigma Microsoft uses is not for me, I prefer Apple's…
I'm fascinated to know what is "natural" about Apple's approach. I think it is "natural" because you are used to it. To me, it feels overly (/incredibly) app-centric. Both Android and Windows Phone (to differing degrees) feel far more task based: "You have a photo. What would you like to do with it?", as opposed to "You opened Instagram? I assume you want to do stuff with photos".
By example, when I look up a contact in my address book in Windows Phone, it allows me to look up my history with that person. Emails, texts, IMs, tweets, everything- all in one place, because who thinks "Dave tweeted that at me" over "Dave sent that to me"? By contrast, iOS keeps every interaction siloed in-app.
Apple's most "natural" interactions result in making the address book look like a leather bound book.