I've heard frequently from people who bought the original Wi-Fi-only iPad about how they planned to upgrade to the iPad 3G as soon as possible.

After spending a couple weeks with an iPad 3G, though, I don't think the upgrade will be worth the price to everyone.

While 3G connectivity is great for checking e-mail or browsing the Web, watching streaming video on the iPad over a cell connection is slow, frustrating and unsatisfying.

And making phone calls over the Internet on the iPad is nearly impossible at the moment.

The iPad 3G is almost identical to the Wi-Fi-only model.

The differences: Instead of an all-aluminum enclosure, there's a black plastic strip along the top to allow 3G reception, and the 3G model weighs 1.6 pounds; the Wi-Fi model, 1.5 pounds.

DATA DECISIONS

The machine comes with a mini SIM card, just like a cellphone, to connect to AT&T's network.

There's no contract; you pay month to month. It's $14.99 a month for 250 megabytes of data downloads or $29.99 for unlimited downloads.

I'd suggest starting with the 250-meg offer and then upgrading as needed, since 250 megs is more data than you might realize.

Plus, you'll generally want to connect to faster Wi-Fi networks whenever possible, and that will reduce the amount of data you'd otherwise download over 3G.

After spending some time with the iPad 3G, I really appreciated Wi-Fi. The problem: 3G simply can't do all the media streaming for which the iPad is designed.

I loaded ABC's video player and the Netflix streaming app on my test unit, switched off Wi-Fi and tried to watch some shows and movies through those two apps, as well as through the built-in YouTube app.

Depending on 3G signal strength, video quality ranged from merely a bit worse than Wi-Fi to shockingly bad.

Occasionally, the ABC player couldn't even load the main menu, much less the actual videos.

And when videos finally started to play after a few minutes of loading and buffering, the image was a smeared, low-resolution mess with frame rates in the single digits.

A few minutes of choppy playback generally led to a somewhat improved picture quality.

But watching the same video side-by-side over Wi-Fi on another iPad was simply depressing. I've posted some screen grabs from the two videos on our technology blog (techblog.dallasnews.com), and the differences are obvious.

And not only was the video quality better, but the loading times were much faster over Wi-Fi _ seconds compared to minutes.

I don't think this is AT&T's fault. I suspect any 3G network in existence would choke trying to provide sharp, smooth video on such a large screen.

Streaming video to a tablet is really a task for the next-generation 4G networks, which all the major carriers will be lighting up this year and next.

KEEP YOUR PHONE

I was also disappointed by the current crop of 3G VoIP apps available for the iPad.

Skype doesn't yet support 3G calls (only Wi-Fi), and I couldn't get Fring, another free VoIP app that claims to offer 3G support, to dial.

I was finally able to achieve modest success with the free VoIP app Whistle. But it took several tries to get a connection, and my one completed call dropped after about 10 seconds.

Needless to say, the iPad is not yet a replacement for your iPhone.

However, being able to surf the Web and check e-mail from anywhere is truly a killer app for the 3G iPad, and it makes this much more of a business device for travelers who don't want to have to rely on Wi-Fi for quickly checking messages or news headlines.

If that's what you want out of your iPad 3G - rather than a way to watch episodes of House on your bus ride to work - then this is indeed a worthy upgrade.

Otherwise, wait for next year's iPad 4G.

IPAD 3G

Pros: As an e-mail and Web machine, the iPad 3G is superb. And pricing for 3G data plans is reasonable and flexible, a solid move from AT&T.

Cons: Streaming video is still much better suited to Wi-Fi, though, so don't expect your iPad 3G to become a mobile multimedia powerhouse.

Bottom line:
The iPad 3G isn't the slam dunk upgrade you might have hoped for. But for some users, the extra cost will be well worth it.

(c) 2010, The Dallas Morning News.

Distributed by McClatchy-Tribune Information Services.