And, perhaps most interestingly, the five tablets are running four different operating systems. So let's compare how the three newcomers stack up against the hottest tablet yet released.
In terms of releases, Motorola won't say anything about the Xoom's UK release date, though it is pencilled in for the first quarter of 2011 in the US. However, it depends on when Google is planning on getting Honeycomb out the door. Likewise we should be seeing the PlayBook arrive in the Spring or early Summer Likewise, it shouldn't be too long before the Samsung Galaxy Tab 10.1 appears. But HP has been a little more coy and we could even see the HP TouchPad arrive in the autumn.
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And, of course, we're also expecting iPad 2, so we'll be updating this piece when we know more about that new device.
This is the biggest difference between the five tablets. The iPad runs Apple's own iOS, the Moto Xoom and Samsung Galaxy Tab 10.1 both pack Android 3.0 Honeycomb, the BlackBerry PlayBook runs RIM's own Tablet OS and likewise the new HP TouchPad also has a bespoke OS. The Touchpad will run Palm's webOS, first developed by Palm - who HP then bought. The tablet will run webOS 3.0.
WEBOS: HP bought Palm and is now taking full advantage of its webOS platform
The Motorola Xoom was the main unit used to demo Android 3.0 Honeycomb at this year's Consumer Electronics Show, though we only saw videos of OS features running on the new device. We're expecting to see a whole lot more of Honeycomb at this week's Mobile World Congress 2011 in Barcelona.
GALAXY TAB 10.1:Named after its screen, it also runs Android 3.0 Honeycomb
There will also be no Motorola MotoBlur interface overlaying Android 3.0 – this could be part of a bigger move by Google to stop having so many variants of Android.
We got hands on with the BlackBerry PlayBook at CES a few weeks ago and it's a serious threat to the iPad's dominance of the sector. TechRadar's Reviews Editor James Rivington says the PlayBook "could well be the tablet that changes the game. In a word, it's a triumph."
ANDROID 3.0: This Xoom was just running a video, but the real Honeycomb looks special
All five units use ARM-based silicon. The iPad runs Apple's own A4 processor clocked at 1GHz (it's less in the iPhone 4), while the Xoom is plumps for a dual-core Nvida Tegra 2 processor, capable of 720p video or sending 1080p full HD to your TV via HDMI. The Samsung Galaxy Tab 10.1 also goes for a 1GHz Nvidia Tegra 2.
The PlayBook is also running a dual-core 1GHz Cortex-A9-based processor, though there are no more details on who has manufactured it. It's probably an Nvidia Tegra 2. The HP TouchPad has the best processor yet announced though - a Qualcomm Snapdragon APQ8060 dual-core running at 1.2GHz.
The Motorola Xoom has a 10.1-inch, 1280 x 800 display. That makes it the largest of the tablets. Like the iPad, the HP TouchPad has a 9.7-inch display with a resolution of 1024 x 768.
Like the Xoom, the Galaxy Tab 10.1 is sporting a 10.1-inch, 1,280 x 800-pixel display - the screen size gives the name.
The PlayBook is only a 7-inch tablet and to us it can feel small. The touch on the PlayBook does extend right across the bezel though, which is a nice touch and pretty important for navigating around the OS.
The screens on both the PlayBook and Xoom look pretty spectacular even under the bright show lights where we checked them out. The PlayBook's size gives it an advantage though, as we said in our Playbook hands on:
"The PlayBook's 1024 x 600 resolution isn't far off the 9.7-inch 1024 x 768 iPad, but because of the Playbook's 7-inch display, the increased pixel density makes all the difference. It's sharp and crisp, and 1080p HD video looks fabulous."
CRISP: The PlayBook's screen is quite pixel dense - largely because it's only a 7-inch tablet
Storage and memory
The Xoom has a Micro SD slot, but Android 3.0 doesn't yet support it (apparently). However, Moto says that as soon as the OS permits it, you'll be able to use up to 32GB of removable storage. As you'll know, the iPad doesn't have any kind of slot – though it has 16 or 32GB on board flash storage of course. Once again, the HP mimics the iPad's approach - no slot, but 16 or 32GB of on-board flash. The Samsung also goes for 16 or 32GB options.
The PlayBook has 1GB of RAM, as does the Xoom. Remarkably, the iPad lags behind in this department, though you'd scarcely notice it. It has 256MB of system memory. There are no details on the RAM inside the HP TouchPad or Samsung Galaxy Tab 10.1 as yet, although we expect they have 1GB.
While the iPad doesn't have a camera, the iPad 2 will change this. The Xoom has two cameras front (2MP) and a 720p capturing back 5MP camera with a dual LED flash. The Playbook packs two cameras – a 3MP front-facing camera and a 5MP rear-facing one. Unusually, the HP TouchPad doesn't have a rear camera, only a front-facing 1.3 megapixel one. However, the trump card belongs to Samsung - there is also an 8MP rear-facing camera. But this is coupled with a poor 2-megapixel front-facing offering.If you want ot shoot video, then this will be done at 1080p Full HD video, 24fps.
FRONT CAM: But HP's TouchPad has no rear camera
All five are designed for use with 3G networks. However, we may well get a Wi-Fi version of the PlayBook before we see a 3G-enabled variant – obviously this is speculation currently. This also looks likely with the HP TouchPad. The base iPad is also Wi-Fi only of course. It looks like there will also be two versions of the Motorola Xoom. Another version will work on 4G networks in the US, though we'll only get 3G here of course. All have 802.11 a/b/g/n Wi-Fi. HP has also promised a 4G version of the TouchPad in due course. The Samsung Galaxy Tab boasts HSPA+ HSPA+ and Bluetooth 3.0.
The Xoom and PlayBook also support HDMI output to a TV – the iPad supports AirPlay for wireless streaming via Apple TV. All have Bluetooth 2.1 plus GPS support. The Xoom and PlayBook also have Micro USB while the iPad sticks with the trusted Apple dock connector. All five tablets have 3.5mm headphone jacks. The PlayBook can be paired with a BlackBerry phone via Bluetooth for full interaction with its Email, Calendar, Docs and BBM.
Location and sensors
All five have an accelerometer (three axis in the Apple and Motorola) and compass plus Assisted GPS in their 3G variants. The Xoom also features a gyroscope as well as a barometer for measuring the atmospheric pressure while the HP PalmPad has a gyro. Details seem sketchy on whether the PlayBook will have a gyroscope, so we're keeping an open mind.
GYRO: Will the PlayBook have a gyroscope like the Xoom?
Rumours abound that the Motorola Xoom price is £720 and we shouldn't expect to pay much less: the firm's VP of international marketing, Andrew Moreley, says "the Motorola Xoom is clearly a premium device with premium prices inside. This will show in the cost." All of which makes the iPad look like a steal. The Wi-Fi version was £429 at launch of course, but the VAT rise has seen this increase to £439. There are no details from HP on pricing, while the PlayBook also doesn't look like it will be as cheap as the iPad. There are as yet no pricing details on the Samsung Galaxy Tab 10.1, though it will be available on subscription from Vodafone.
The 7-inch PlayBook is 9.7mm thick and weighs just over 400g, which beats the Samsung Galaxy Tab 10.1 at 10.9mm and 599g.. The weight of the 10.1-inch Xoom has been reported to be around 730g, with a 13mm thickness. The HP is similar - 14mm thick and weighing in at 740g. That's roughly the same weight as the Wi-Fi + 3G iPad, which is 13.4mm thick.
As most of the world's population knows, the iPad doesn't support Flash. Android 3.0 does though, as does RIM's Tablet OS, with full Flash 10.1 and Adobe Air. WebOS also has Flash 10.1 All have HTML 5 compatibility. Will Android 3.0 and RIM's new OS really lay down the gauntlet for iOS and the iPad? Only time will tell.