Sprint customers: If you're worried that you bought a first gen Palm Pre only to watch helplessly as Palm released a better Pre on Verizon, stop. The Palm Pre Plus is essentially the same phone as the Palm Pre.
Sure, there are minor hardware differences—most notably the doubling of the RAM and the storage space—but it essentially feels like the same phone.
What's changed in the hardware

The three most visible changes you'll notice are the removed front button, the matted inductive-charging-capable backplate and the slightly improved keyboard.
Palm realized with the Palm Pixi that a front button was unnecessary, since it broke up the smooth finish of the face, and replaced it with a touch-sensitive button instead. It's what the Pre should have been like in the first place. The new touch button works fine, and within a few minutes you'll barely even miss the hardware key like you would never miss a sixth toe you never had.
The keyboard has been upgraded as well, made much less mushy with more tactile feedback when you hit a key—another lesson Palm learned from the Pixi. You'll type faster and more accurately with these keys compared to the original Pre, even though they don't raise up any higher off the body and their layout remains unchanged.
As for the Touchstone-compatible inductive backing, which is available as a separate purchase previously on the Pre, that upgrade comes standard on the Pre Plus. By subsidizing the Touchstone hardware with the new Pre itself, Palm effectively lowered the cost of their inductive charger by $20 ($70 on Sprint, $50 on Verizon), which makes the accessory all the easier to justify buying. Even if you don't go the wireless charging route, the matted, inductive finish makes the phone a lot classier and less prone to fingerprint smudging.
Everything else is the same

That same cheese-cutting bottom edge of the phone is still there, and the overall mold of the device is exactly what we saw with the first Pre. There's no change in camera, processor, graphical capability or screen. And, luckily for Pre owners, the software is identical, too.
Basically, if you didn't like the original Pre, you won't like the Pre Plus any more than before. But if you did like the Pre and didn't want to jump to Sprint, Palm's graciously brought it to you.

How does it compare to the original in performance?

Both phones took almost exactly two minutes to boot up, side by side. Flicking around, browsing websites, listening to music and answering emails—in any of these routine tasks, you'd never tell the two phones apart through blind testing. However, there is a slight difference when you start getting to heavy multitasking.
The increased RAM starts to be utilized when you open a LOT of apps—I'm talking about ten or more, something you normally wouldn't do unless you were really bored, really forgetful or really lazy about closing your apps. Once you have all these things open at once, you'll notice that the old Pre takes somewhere between 5 to 10 seconds longer to start up new applications than the Pre Plus. While this improvement may be handy for some, the fact that the discrepancy is only 5 to 10 seconds is a testament to how well the multitasking memory allocation worked in the original Pre. Once all these apps are open, there isn't much difference, but switching around is a bit faster.

Mobile Hotspot

While the Sprint Pre lacks tethering, Verizon's Palm Plus includes an excellent Mobile Hotspot app that's quite simple to use. It's essentially the same as other tethering apps out there: Fire up the app, set a hotspot password and switch on the tethering. Any Wi-Fi device (laptops, phones) will see the broadcasted network and be able to connect to it as you would any other hotspot.
And Verizon, although not the "fastest" 3G network, still gave pretty damn good speeds when I was testing this feature—and it's reliable to boot. The only downside is the pricing, which we'll cover later, but having a portable MiFi that's also your phone can be a lifesaver if you need to connect from the field.

So that's why Palm called this Plus

There isn't enough to call this an entirely new series of Palm phones, or even a Palm Pre 2. The Pre Plus improved on the Pre in a few important regards, don't get me wrong, but it's essentially the same phone we've seen for the last six months. You won't notice the increased memory unless you're a habitual window-opener, nor will you appreciate the keyboard unless you really had a problem with the previous one.
So yes, it's called the Palm Pre Plus for a reason. And it lets Verizon customers get in on the web OS action while staying on their preferred network—which is a good thing, and actually a decent move for Palm. Rather than try to suck more money off the same group of potential customers (Sprint users) with a phone that will be a bit better but not all that different, Palm went ahead and repackaged the same phone with slight modifications to a new sea of potential users.
I suspect that this strategy will grant Palm more return on their initial webOS/Palm Pre investment, justifying the production of an entirely new phone that catches up to both the Nexus One and the upcoming iPhone 4. For Palm's sake, it better.

The Palm Pre Plus will be $150 with a two-year contract on Verizon, and the Pixi Plus will be $100. That's the same price as it is currently on Sprint—even though Sprint had some deals earlier to push their Pre down to the $100 range.
But, Verizon has a special deal where you can buy either a Pre Plus or a Pixi Plus and get one free Pixi Plus after mail-in rebate, if you want to switch your family over to all Palms.
Here's the bad. The 3G hotspot feature will be an extra $40 on top of your existing voice and data plans, and it won't be unlimited! Verizon will give you 5GB and charge 5 cents per MB that you go over. It's pricey, but nice to have in an emergency.

And here are the voice plans that go with. You'll be able to buy the Pre Plus and Pixi Plus January 25.
More RAM and storage means a slightly better experience, but you might not notice it

Keyboard is improved

Hotspot tethering app is somewhat unique, since it's officially sponsored by the provider

Still a fan of webOS as a smartphone platform, and it's still in good shape here

Still not as many apps as Android or iPhone yet

It's basically the same phone as the Palm Pre

Hotspot access is expensive
Background can be found here

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