Blackberry Z10Update I switched to using the Q10 because of its excellent keyboard - however blackberry has dropped the ball on this device - the screen's brightness is half that of the Z10 and darker than even the 9800. I didn't think to check the brightness before I purchased a $900 replacement for my Z10.
I have been a loyal user of RIM/Blackberry devices since the 957 around 2000. The Z10 is around my 8th blackberry and the first that has left my belt clip. Previous versions of the blackberry OS up until 6 had performance and crashing problems that usually only occurred under load (like opening more than 5 tabs in the browser.
I have however found a bug in the new QNX blackberry 10 OS that is quick to reproduce.
Open calendar, switch to month view, add an event and try to change the time in the date roller - the application will terminate and send you back to the home screen. The workaround is to accept the current time and then reenter the item and modify the date.
I am also an owner of an iPhone 4s, an Android 2.2, and Android 4.2 tablet and a playbook, I like the Blackberry Z10 better than all of them.