I previously bought and used the SPIGEN Ultra Crystal Screen Protector for an iPhone and was very pleased. Needless to say, this one for the Blackberry Z10 is just as wonderful. It is so clear that, if it were not for the cutouts around the front facing camera and LED notification light, you could simply not tell that it is on!
While the steps of the application were easy, as always, I found that getting it on straight was a bit more of a challenge with the Blackberry Z10, compared to the iPhone, as there is not a big "Home" button (like on the iPhone), to act as a reference point. But with a little bit of careful attention and patience, it will only take you a few minutes to have it placed.
All SPIGEN Ultra Crystal products I have used have gone on seamlessly and look great. Personally I believe that this is the highest quality screen protector on the market, and the only one a person should buy!