RIM is expecting shipments of 1 million BlackBerry PlayBook tablets in Q1 2011, with the first models being WiFi-only and 3G. Quanta Computer has already begun volume production of the BlackBerry PlayBook, according to industry sources cited by DigiTimes.

The 4G WiMAX PlayBook on Sprint will come in Q2 2011. It will take on Verizon's LTE version of the Motorola Xoom, to be released in the same quarter. In fact, it looks like RIM's first target will be Motorola. Earlier this week we learned that the company has placed orders for about 700,000 to 800,000 units of the Xoom.

Let's compare the specifications for the two devices. The 10.1-inch Xoom (1280x800 resolution) will ship with Android 3.0 (codenamed Honeycomb) running on Nvidia's Tegra 2 processor, 1GB of DDR2 RAM, 32GB of onboard storage (expandable via SD), a 2-megapixel camera on the front, a 5-megapixel camera with dual LED flash on the back, a micro USB 2.0 port, HDMI out, 802.11b/g/n Wi-Fi, as well as Bluetooth 2.1 + EDR. The 7-inch PlayBook (1024 x 600 resolution) will ship with QNX running on a 1GHz dual-core ARM Cortex A9 processor, 1GB of RAM, dual HD cameras with support for 1080p recording (3MP in front, 5MP in back), 1080p video playback support with HDMI output, 802.11a/b/g/n, USB, and Bluetooth connectivity with other BlackBerry handsets.

It seems to us like the biggest factor will actually be size: do you want a bigger screen and thus a heavier device, or would you prefer a smaller screen but a lighter device? Even if you answer this question, there are still many more tablets shipping this year that you can choose from. It's definitely enough to make your head spin, even wonder whether you want a tablet in the first place.