On the whole, I really like my PlayBook. That said, there are certain UI decisions that make absolutely no sense and are in desperate need of being cleaned up. One example: the URL bar in the default browser.
Landscape Mode

The UI makes loads of sense here. No major issues, though the decision to have the history icon (counter-clockwise circle) dead beside the refresh icon (at the end of the URL bar) is a boneheaded given the imprecision of the touch interface.
Portrait Mode


Note that to get the full browser options in the second portrait screenshot, you need to slide your finger along the favourite icon to reveal the other options. This is not an intuitive decision. Note that, with the poor precision of the touch controls, having the history button beside the refresh button is an even worse decision in portrait mode than when in landscape.
Truly WTF Decision
Note that in all the above screenshots there is a medal-like icon to the left of the URL. Tapping it brings up the below screen.

99.99999% of the world will have no clue what this means. For those of us that do it’s confusing: I’ve had the browser tell me on multiple occasions that the certificate is invalid when I know that not to be the case. I get that certificate awareness is a security plus but it’s done so poorly here that it’s (at best) effectively meaningless.
Now, are these huge issues? No, of course not. Are they signs of an unpolished OS release? Most definitely. Hopefully they’ll be improved upon in the 2.0 release of the PlayBook OS.