The plan

As I noted in my first look at the 3G iPad, managing your AT&T account on the iPad is simple: you can sign up, monitor your usage, change your plan, and even cancel it all from the iPad's Settings app. While no contract is required, do remember that the data plans are prepaid, so once you activate a plan, you've got it for 30 days. Changing or cancelling a plan won't take effect until the end of the billing cycle.

Of the two plans offered through AT&T, which should you get? Well, the ability to subscribe and cancel at any time is a hugely beneficial one: it means you only have to sign up for 3G service when you need it, say when you're traveling for example.

But if you're doing anything beyond email and light web surfing, you'll probably want to shell out for the unlimited plan. Streaming video, in particular, is hugely intensive: using the Netflix application can easily rack up in excess of 100MB in an hour. One feature length movie can put you within spitting distance of your bandwidth cap.

There are cases where you might opt for the 250MB plan. As one of my colleagues suggested, perhaps you might want to check your email or get online while you're staying at a hotel that charges, to put it diplomatically, premium fees for Wi-Fi access. It may very well be worthwhile, in such a case, to shell out the $15 just for the convenience. Plus, even the cheaper plan gives you the added bonus of free access to AT&T's nationwide network of more than 20,000 Wi-Fi hotspots, including one at each of the half dozen Starbucks that are no doubt within walking distance from your location at this very moment.

Usage meter

If you want to keep an eye on how much bandwidth you're chewing up, there are two options: one is to use the meters under Settings -> General -> Usage, which tell you how much data has been sent and received over the cellular data connection. This information is tracked by the iPad's operating system itself, so it should always be up to date. You can also view your bandwidth usage under your AT&T account in Settings -> Cellular Data, but that can sometimes take time to update as it's tracked by AT&T. In addition, if you're using the unlimited plan, you won't see your usage displayed there, just a note that you're on unlimited bandwidth.

Given the disparity between the prices and amount of bandwidth offered, I think most users will opt for the unlimited plan. If you hit the 250MB cap, AT&T shuts the service off unless you add another $15 chunk of 250MB or switch to the unlimited plan, and if the choice is $30 for 500MB or $30 for unlimited data, that's not decision that requires a lot of thought.

One downside to 3G connectivity through your iPad is that even if you already have an iPhone, with its attendant $30-per-month unlimited data plan, you'll need to pay for the iPad's data plan separately. All of a sudden, you're racking up $60 every month for 3G data, and if you have more than one 3G-enabled iPad in your family, you'll have to pay full price for each one since AT&T doesn't offer any sort of family plan.

The power

The addition of cellular capability to the iPad raises another question: how does the device's battery life hold up? While Macworld Lab is still conducting more definitive testing, my informal experience suggests that the 3G connection does impact the bottom line for power, though not as badly as you might fear. While relying on the cell phone connection, I saw the battery power dip much lower than it had on any day while using the Wi-Fi model, but not so much so that I was unable to get a full day's use out of it.

But remember that the addition of 3G support means that the iPad carries three separate radio chips that can all be active simultaneously: the cellular connection, Wi-Fi and Bluetooth. Having all three of these on at once can definitely put a dent in your battery. In fact, a solid day's worth of mixed usage, from about 8:30 AM to 5:30 PM, dropped me as low as 40 percent of battery life, which is lower than I reached in daily average usage of my Wi-Fi iPad in the previous weeks.

You have the ability to deactivate the cell connection under Settings-> Cellular Data and rely only on Wi-Fi. And that's a welcome option, especially if you spend a lot of time in a location where the iPad struggles to get a solid signal. I've taken to leaving the cellular data connection off unless I'm specifically out of Wi-Fi range, at which point the battery life ought to more or less be equivalent to a Wi-Fi-only iPad.

OUR VERDICT

The 3G iPad is every bit as good a device as the Wi-Fi-only model, and it's only more capable than its fellow model. There are no significant tradeoffs with the 3G version, as long as you're willing to pay more in exchange for more capability. My colleague Mr. Snell made the case for a 3G version of the iPad well before it shipped, and having one in my hands, I find myself inclined to concur with his conclusions, that 3G connectivity gives this version of the iPad a measure of flexibility missing from the Wi-Fi-only version.

Assuming you're already sold on the idea of an iPad and merely want to figure out whether to buy the 3G version or the Wi-Fi-only model, the real question you need to ask yourself is: is it worth it to spend an additional $130 to have the option to use 3G service? Look at it as an investment that at some point down the road you'll be trapped somewhere without Wi-Fi, and you'll be glad you can still play that triple word score.