Build it and they will come: That seems to be Apple's mantra these days, and if the lines that formed in front of Apple Stores all around the Unites States this past Saturday are any indication, the Cupertino consumer electronics giant could have another hit on its hands. That's when Apple's eagerly awaited iPad went on sale, and according to the company, it sold more than 300,000 units on its first day.

"It feels great to have the iPad launched into the world—it's going to be a game changer," said Apple CEO Steve Jobs in a prepared statement. "iPad users, on average, downloaded more than three apps and close to one book within hours of unpacking their new iPad."

300,000 is a big number, and certainly the iPad is on track to outperform any previous tablet-like devices, including the slow-selling Tablet PCs that Microsoft first championed a decade ago. But that figure is much lower than estimates—Piper Jaffray analyst Gene Munster had pegged the figure at over twice that, or up to 700,000 units—and it includes presales, so all the sales didn't really come on that first day. And to draw an obvious comparison, when Apple launched the iPhone 3GS last year, it sold 1 million units in three days. It's likely that iPad sales petered out after the initial burst of excitement ended Saturday.

Apple's popularity with its own fanbase isn't in question, and while these people can and will fill lines at Apple Stores, the reality is that Apple is also a very powerful brand among the general population, thanks to hit products such as the iPod and iPhone. So even a tweener device like the iPad—which is neither computer nor PDA, portable but unable to fit in a pocket—will generate some excitement. The question is: How much? And how long will it last?

The issue, as always with Apple products, is a combination of price and compromise. The iPad starts at $500, which seems low (for Apple) but is in fact high compared with what consumers are used to paying for non-Apple PCs. And for that non-trivial $500, you get the entry-level iPad only: It comes with just 16GB of storage (vs. the 2GB to 4GB of RAM in a typical $500 PC and the 320GB to 500GB of hard drive storage), enough for only a handful of movies and a small music collection. At these prices, the iPad should be able to replace some device, but it can't. It's an accessory—a pricy and unnecessary accessory, and that fact will likely further dim demand going forward.

Apple will do what it always does, of course. After the initial sales bump is over—and it appears to be over, in the United States, at least—it can lower prices, improve the software, and, over time, change the hardware to address deliberately missing features like a camera and more storage. That will trigger a second round of purchases as early adopters shed their initial machines for the new models. And Apple can duplicate its day-one excitement by releasing the iPad, over time, in other, non-US, markets.

As for my own iPad, it's undeniably disappointing, in part because of the unrealistic expectations generated by the media hype, and in part because it simply underdelivers in key areas. I'll be reviewing the iPad soon, but my initial impressions are largely negative: It's too big and heavy, it's too expensive, and it doesn't work well as an eBook reader because the screen is far too reflective. And while I was hoping for a highly portable movie player, the iPad's large 4:3 screen makes today's widescreen movies look tiny and compressed. I'll keep testing it, of course. And it does have some positive aspects, including snappy performance and a swelling apps store. It's no disaster. It's just not necessary.

And that, I think, is the iPad in a nutshell.