Nick Bilton, at the Times, addresses the question, with a little help from Tim O'Reilly. I like what O'Reilly (who recently ditched his iPhone for a Nexus One) has to say on the matter:

Ultimately, Mr. O’Reilly said he made the switch because he found the wireless service to be less expensive. And he liked that Google’s Android platform was more open to developers than Apple’s iPhone ecosystem.

That, my fellow Internauts, is what it's all about. The iPhone is a beautiful device, but it's too restrictive, plain and simple. The Nexus One has its problems, as Gen 1 devices so often do, but that's to be expected (and why I haven't bought one myself); what's important is that comparable alternatives are finally beginning to emerge, and that'll force Apple to either open up its platform and add a little transparency, or start ceding ground to the competition.

I've resisted the iPhone mainly for that reason -- because it offers pretty much no flexibility whatever. It's practically bound to a pricey AT&T contract, doesn't fully support Flash, doesn't support Java at all, and its app store requires me to pay Apple a hundred bucks just for the privilege of building apps in Objective-C -- a language almost nobody uses but Apple -- and then cross my fingers in hopes that my app, which could take months to build, might be so lucky as to be approved by the all-powerful App Store demigods. Oh, and I'd have to buy a Mac, too -- one can't develop iPhone apps (legally, anyway) on anything but a licensed Mac OS. Don't like it, Nunciato? Tough. Suck on that.

Android, on the other hand, is way more open: it runs plain ol' Java, which millions of developers (me included) already know, it builds nicely with Eclipse on all three major platforms, and developing for it doesn't cost me a penny. I can build and deploy apps to my heart's content, then reuse the knowledge I gain elsewhere. So, let's see: closed, expensive and risky, or open, free and predictable? Hmm. Lemme think....

Locking down the iPhone ecosystem will, I think ultimately, turn out to be a major mistake on Apple's part; it was only a matter of time until alternatives would begin to emerge, and folks would start realizing the hidden costs of carrying around such a pretty little device. Personally, I'm waiting -- not for Apple to change its ways, because I don't think that'll happen (although it'd be great if it did), but for the Nexus One to stabilize, and for the Android universe to expand a bit. Then, maybe, I'll bite. For now, though, I'll stick with my iPhone wanna-be. It's far from perfect, but it works, and it doesn't pretend to be more than it is.