Apple revealed its new Series 3 watches, as well as what's in store for iOS4. (Apple)

Apple has a new Watch — and it more or less looks the same as the last one. Although its appearance hasn't changed much, however, this is one instance in which under-the-hood changes make a huge difference. The Watch can now connect to a cellular network, which fixes the most annoying thing about the older versions: that they relied so heavily on your phone.

The new Apple Watch is slightly thicker than the last version, but the difference is so minimal that you'd hardly notice. Apple executives on stage said the difference was about the same as two sheets of paper. Practically speaking, there was no noticeable change. That's admittedly impressive, given how much more Apple has stuffed into this Watch.

What will get noticed? Speed upgrades. The new chip in the Apple Watch Series 3 makes it downright snappy. If you are an early adopter looking to upgrade, you'll want to skip the Series 2 and jump to the Series 3 — the speed improvement is noticeable. Things are also snappier when talking to Siri, which suffered from some considerable lag on older Watches.

Unfortunately, there wasn't a way to test phone calls at the demo, though you could see how one could place them and there were watch faces that made it easy to tell you how much signal you had.

However, phone calls on your Watch probably won't be the thing you want to use your cellular data for the most. Calls on the wrist are, quite frankly, awkward. (No one tell Dick Tracy.) They might be better with the addition of wireless headphones, but your phone is still probably going to be your primary tool for that.

While calls are useful proof of cell connection, they aren't really what connecting a watch to an LTE network is all about. The point is to be able to do things without needing to carry your phone along — and that's useful in plenty of other ways, especially for Apple's core watch audience of fitness buffs.

And using apps such as Maps and Music on the go without having to take your phone along is a game-changer. Those are the kinds of functions that made you feel tethered to the Watch. Knowing you also had to strap your phone on to go for a run with Watch probably made it much harder to justify the price of such a gadget. After all, you had your phone for music, for directions and for recording your steps. Without your phone, the Watch was more or less a really expensive dumbwatch.

Now, with the Watch free of the phone but with the same access to Apple's App Store, there's at least a more compelling reason to spend $399 for it if you've been eyeing it.

Here's the thing to remember before you rush out to buy it, though: The Apple Watch Series 3 will require its own data plan. AT&T, T-Mobile and Verizon have all said that the Watch Series 3 will cost an additional $10 per month for as long as you have the Watch. Sprint has said it will support the Watch, but it hasn't said for how much.

Those aren't wallet-breaking prices, but that steady expense is worth remembering as you factor in the cost of the Watch. Still, for those who've been waiting for Apple to catch up to other competitors such as the Samsung Gear line and add cellular connectivity, it's a welcome addition.

Apple is also releasing a noncellular version, which will run you $329. You'll still get the speed improvements, but not as much freedom, which may be just fine for people who aren't looking to off-road with their phones.

The price of the Series 1 Apple Watch, the original version, is now $249 — a move that Apple may hope will lure in those who were sitting on the fence. That still feels a little high for people who've been waiting for the price to drop, given how much slower and more limited it is in comparison with the new version, but it is a good entry-level option for those who want it.

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