I've had Zagg's since I bought my phone a couple weeks ago and I still go back and forth on it.
Installation isn't as bad as some people here made it out to be, but it's not a fun task either. I didn't get any bubbles when I installed it though.
The protector itself is obviously strong, but I definitely think that sensitivity suffers.
I didn't get any of the rainbow streaks some people did, but it definitely feels rubbery. I've gotten used to it, but I used a non-zagg'd screen today and it was really much nicer and responsive.
One interesting thing is that I installed it and there was a speck of dust under it so I tried to reinstall. While I was reinstalling, I apparently scratched or bunched the protector itself with the card they give you to install it, so that was a bit odd. I'll probably send in for a replacement.