First, I bought the bumper. It is a good bumper. Nice fit and quality. The rubbery edge gives good grip and addresses the concern about setting it on a marble counter over a piece of grit. Next the screen. I have a couple of watches with mineral glass crystals, and can attest to their ability to survive shock and rough use. But while those crystals have survived amazing abuse, they also scratched when addressed by sand and such. So, I sought screen protectors, front and back.
Application instructions don't come with the package, but are available on the company website. Installation went as it should, and turned out well. The only issue, the die cuts are designed to be "Bumper Compatible". This seems to mean they are a few microns too small to go to the edge of the glass on front and back. The bumper actually fits flush to the edge of the screen protectors, not over them. OK, with a bumper installed, great. Without, there is a bothersome edge I can feel just inside the edge of the iPhone screen.
The clarity is as clear as it can be, I think, I can't perceive any difference in the Retina Display. The faux leather back is just right. Not too sticky but with some texture to make it a more sure grip. But... the front screen is slightly grippy feeling, it is not as slick as the glass. This may be a problem. It is not enough to impact the scrolling or function in any way, but it does not feel as good. Maybe this will "break in".
Is it worth $19 (including shipping)? That is completely relative. It does what it says, and does it well so far.
Update: the screen saver is a fingerprint magnet compared to the fanstastic oleophobic coating Apple uses on the glass, and the whole thing looks rather, oh, downmarket. Like the BB Bold.