Many of the rumors about the iPhone 4S and iPhone 5 included a claim that Apple was planning to increase the size of the screen, from its current 3.5 inches to 4 inches. And, while it wasn’t clear if there would be both a larger-screen and the standard size, or whether the newest iteration would come only in that larger size.
The design of the iPhone is certainly a hot topic, and of course, all of design is navigating the trade-offs, but the quick analysis and comparison that Dustin Curtis did is quite nice. The green shading indicates the area covered by the thumb of the hand holding the device (I’m not sure, but I bet it’s estimated with Dustin’s hand, and not the 95% percentile used in ergonomics; still quite telling though).

But what’s even nicer is this claim by John Gruber at Daring Fireball:
But I do think there’s a ‘Pepsi Challenge’ type effect going on here. The thing with the Pepsi Challenge was that most people preferred (and prefer today) the taste of Coke over Pepsi, when drinking a full serving. But, when you only take a sip or two of each, people tend to prefer whichever is sweeter, and that was Pepsi. Some people really do prefer Pepsi, of course. But I think there are a bunch of people buying big-ass Android phones after taking just a sip or two in the store.
This seems very right to me. And then just over the weekend, I read an academic paper which includes a framework to explain long-term product use and appreciation [PDF]. It also coincidentally includes a study about smartphone features and what design elements are salient under different time-spans. During the lifespan of a product, the user’s feelings, attitudes and conceptions change, but so do the very metrics that they use to measure and qualify their experiences. Below is a visual representation of the model that the authors use in the paper (and in a system they’ve built to collect these kinds of data), but I highly recommend reading the whole thing if you’re interested in long-term issues in designing the “right” thing, be it physical or virtual.

[PDF] at Dr. Karapanos’ site. Citation: Karapanos, E., Zimmerman, J., Forlizzi, J., & Martens, J. (2010). Measuring the Dynamics of Remembered Experience Over Time. Interacting with Computers. Volume 22, Issue 5, September 2010, Pages 328-335.