After months of speculation and rumormongering, RIM has finally unveiled its own tablet. Called the BlackBerry PlayBook, it’s a smaller (7-inch screen) and lighter (by around 35%) alternative to the Apple iPad.

But can it possibly compete?

This video is the official preview video RIM has released in order to promote the BlackBerry PlayBook, and it sits nicely alongside the amateur videos showing the PlayBook in its display case.

Like it or not the Apple iPad is THE tablet that all other tablets have to be measured against at this stage. Because it’s the first truly usable, mainstream tablet, and it has sold phenomenally well in its first few months on sale.

Whether the BlackBerry PlayBook can compete with the Apple iPad depends on many factors. But the most important may be price. Something RIM hasn’t yet announced.