I know it's contrary to another review that was posted here but I just applied (and then promptly removed) my $15 screen protector from Invisible Shield.
To start with, it was cut to small, not by much but it did NOT fit as perfectly as the included HTC protector.
Secondly the squirt bottle for the included fluid did not work, I had to preform minor surgery on it to get it to function at all, and it never did mist like it's supposed to have.
Beyond that, the application is nearly impossible to pull off without smudges or dust under the film; I had zero issues getting my HTC film on and I've put protectors on my Apache more than a few times without half as much trouble.
I do not recommend this product at all.