I have to weigh in on this. If you have a blackberry phone the playbook is fantastic. It lets you extend the functionality almost exponentially.
If you don't have a bb phone, it is still a great device. Stable, multitask capable, high res screen, flash support and since 2.0 it has a pretty nice email client (I use it for yahoo and gmail). I have stopped taking my laptop on trips now that I have the BB playbook. I can get 9 hours of battery life (watching movies in-flight and the occasional game). The form factor, even with the otterbox case, is pocketable in most of my jackets.

If you are looking for an ipad alternative, do take a look at the playbook.
The downside is the lack of apps. There are some pretty nice ones, but less than 1/10 of 1% of those for the apple products.