Count me among the bandwagon bunch. As of today, I'm an iPhone user. The Treo I've relied upon for four years is no longer, finally falling victim to my ham-handedness.

Goodbye, Palm (Nasdaq: PALM). Hello, Apple (Nasdaq: AAPL).

But you knew this was coming, right? I announced my plan to buy an iPhone months ago. (Here, in fact.) Now that I have one, I can say ... yeah, it's sweet. The interface is a breeze. Setup was simple. And while I'd rather be forced to listen to nails on a chalkboard than browse the Web with my old Treo, on the iPhone, it's at worst tolerable and often pretty good.

In short: I'm a happy customer. So far.

And yet, I'll not grave-dance. My Treo was outstanding, a symbol of how great Palm once was and could be again. If, that is, its scientists remember what it was like to invent groundbreaking technology.

By "groundbreaking," I mean the Treo, which combined the most compelling features of a personal digital assistant -- integrated contacts and calendar -- with a phone.

Interestingly, the Treo wasn't the first of its kind. Research In Motion (Nasdaq: RIMM) introduced the game-changing BlackBerry three years earlier, in 1999. The Treo nevertheless made its mark by proving that a phone and a PDA could co-exist. The BlackBerry, by contrast, was emphasizing on-the-go email when the Treo hit shelves in 2002.

But that was then. Today, dozens of firms are building smartphones, including global leader Nokia (NYSE: NOK) and Taiwan's High Tech Computer. Comparing the major models is often a matter of nuance.

Except, perhaps, in the case of the iPhone, whose elegant navigation, excellent Web browsing, and simple setup set it apart in the way that integrated functions once set apart the Treo.

(Sigh.)

Farewell, my friend.

Brrrrring! It's related Foolishness calling: