I've had mine for about a month and what I've noticed is this:
It's great for when there are a few smudges or fingerprints. Just wipe on your pants. It's not great for when your hands are sweaty and there are lots of smudges and fingerprints. Almost impossible to wipe away on your pants. However, if you ignore it for the moment, use it as usual and when you are done put it back into your pocket or wherever, the fingerprints and smudges will be magically gone or much reduced for the next time you take it out.