RIM unveiled its new PlayBook in San Francisco Monday to mixed reviews and several unanswered questions. It became clear, however, that the device shown off at the DevCon keynote proved many of the rumours about RIM's tablet computer to be true, and that RIM hoped to make inroads into the business community, even calling its device the "first professional-grade tablet." (We obviously don't know what it takes for a tablet to lose its amateur status, though.)

However, there are at least five reasons why anyone thinking of buying a PlayBook should wait.

1. The BlackBerry Tablet OS

Built on the QNX Neutrino microkernel architecture, part of a RIM acquisition of QNX Software Systems, the OS is incompatible with other BlackBerry devices. And while RIM says that there will soon be applications that will make them able to talk to one another, so far there are none. Perhaps by making the announcement at a convention for developers, RIM hoped to jump-start the process.

Blackberry PlayBook

2. Unknown Price

So far RIM is keeping mum on a suggested retail price for the PlayBook, which probably means the original price was deemed too high and they have to make it more competitive. RIM should have a range, though, from $499 (the price of the cheapest iPad) to $1067 (the rumored cost for a Galaxy Tab.) I tend to be cynical when companies announce their cool new gadgets but refrain from a retail price, it makes me anticipate a price-gouging. My vote is that RIM's tablet had better be cost-effective to make any dent on the iPad or Android platform market share.

3. 7-inch Touchscreen

While many are touting the 7-inch touchscreen as something new, that doesn't mean it's best for your company. While the almost 10-inch iPad has found a business audience, there hasn't been a big demand for a smaller display. The PlayBook is a slightly smaller device, and less than a pound, but it's too big for pockets, and the font or icons may be hard to read for nearsighted customers or employees.

4. Apps? What Apps?

Applications for the PlayBook aren't even in the development phase yet, unlike its competitors running iOS and Android, whose apps number in the hundreds of thousands. Worse, the PlayBook needs an app just to be able to communicate with a BlackBerry handset.

5. The Joy of Tethering

The PlayBook won't have a cellular carrier, so any Internet access would be through tethering the device to a BlackBerry phone. While some may not find this annoying, try doing this for a few hours, and see how fast your battery life disappears.

Granted, the PlayBook can use Wi-Fi on public networks, but be prepared to share your information with curious neighbors. With two HD cameras, a 1 GHz processor, 1080p video recording and multitasking, the PlayBook isn't without utility or charm, but without substance or a real price, it's not worth considering,especially when the iPad is already available.