iPad open for pre-orders: A decision guide for would-be buyers

Pre-orders for the Apple iPad start Friday, March 12 at Apple.com, for online delivery or to reserve for pickup at an Apple retail store. For those who are considering buying Apple's new tablet computer, at prices that start at $499, the date brings some decisions.

Here's a rundown of some, along with some upshot advice:

Order now or wait until the reviews are in? As with other new products, this decision hinges on the strength of your desire for early acquisition of a new and interesting product—as the iPad unquestionably is—weighed against the risk of bugs or outright flaws in its first-generation version. There are also supply considerations, of course.

In this case, Apple has a fine track record for creating first-gen devices that are ready for market. And limited supply was also rumored to have been behind the delay in availability of the iPad from late March to April 3. Those rumors raise questions about how soon new iPads may be available should the initial supply sell out on April 3.

Upshot: Keeners might want to lean to early ordering. Compared with many other new devices (hello Nook owners!), the risk of disappointing, buggy performance from the initial iPads seems relatively low, and the risk of a longish wait for replenished supplies relatively high.

Which version—Wi-fi-only or 3G/Wi-fi? This complicates the call for early adopters who aren't planning to acquire two iPads. While only the Wi-fi version of the iPad will be available on April 3, pre-orders will also be taken for the Wifi/3G version, to be serviced by AT&T and made available "in late April," according to Apple.

3G capability will add $130 to the price of an iPad, meaning a 3G-capable model will cost at least $629. 3G service will cost $30 per month for unlimited data, $15 for up to 250 MB (FYI, iPhone owners use an average of 273 MB a month, according to exclusive data we recently obtained). However, in contrast to service to 3G-connected laptops and netbooks, a contract will not be required; you can subscribe to 3G when you want it, and drop it when you don't.

Upshot: Your need for 3G depends in part on your expected use of the device, which in turn depends in part on apps that we haven't yet seen. However, if you expect to use an iPad for known apps that will require everywhere access, such as e-mail and location/GPS-based apps, you'll likely want to wait on the 3G version.

Also, keep in mind the experiences of some owners of the iPod Touch, the Wi-fi-only device that's essentially an iPhone without the phone or the 3G access, who express frustration at the widely varying capabilities of their device depending on whether or not it's within range of Wi-fi.

Which capacity to buy? iPads will come in 16, 32, and 64 GB capacities—with a $100 bump up in price for each 16 GB increment. For comparison, iPhones come in 8-, 16-, and 32-GB versions, and iPod Touches in 8-, 32-, and 64-GB versions. The iPad's 9.7-inch screen, promises to make the iPad more movie-friendly than the iPhone and Touch, which have 3.5-inch screens. A downloaded movie requires about 1 to 2 GB of capacity. A typical music album occupies about 200 MB.

It isn't yet known how capacious files from the iPad's iBooks store might be. But Amazon's Kindle, for example, which use their own format, can hold thousands of books in their modest 2 to 4 GB capacities.

Upshot: As with Wi-fi, the right capacity depends a lot on how you think you might use your iPad. If you hope to use it as your primary music player, however, you likely already know how much capacity you'll want for music alone, without even considering other apps and uses.

—Paul Reynolds