The Playbook is actually lovely, & is primarily designed to be a tablet companion for Blackberry users right now.
liking the gesture bezel. Left & right let you switch between active applications, down brings up the application tray, & up is similar to an expanded menu button in Android. The front is buttonless, so you need to get used to the gestures to perform tasks.
The browser works like its supposed to, including Adobe Flash.
Text input is standard fare
The interface usually feels snappy, but you could get animations to be a small choppy in the event you try. It is well optimized & visually engaging.
The default homescreen is a stack of open applications, which you need to close by hand as you switch from task to task. Not positive if there is an upper limit, but as long as you kill the tasks you are not in, it will work fine. As for right now, there's not apps for the thing to let you make the gizmo lag significantly.
Compared to Honeycomb, it feels more intuitive to make use of & far less cluttery. But the cards multitask interface will take some getting used to because it is unique.