After what seems like an eternity, the BlackBerry PlayBook is finally available on retail shelves.  Announced at DEVCON last year, it's available in 16, 32, and 64 GB flavors, and starts at $499.99.  It offers a 1 GHz dual-core processor, 7-inch display, 5-megapixel rear-facing camera, 3-megapixel front-facing camera, and RIM's new QNX platform.  The tablet has a lot of potential, but there are a lot of people that are wary of BlackBerry, given that they've fallen behind the curve in the smartphone game.  Will the tablet suffer the same fate?