If, like me, you don't want to bother with a phone case / cover and you tend to put the phone in your pocket without always thinking to check what's already in there, then you must buy this item.
Positives:
As sensitive to touch / stylus as normal screen.
More scratch resistant than normal screen.
Does not obscure screen visibility in any way at all.
Easy to remove.
Covers minor scratches to allow smooth stylus travel.
Negatives:
Shows fingerprints more than normal screen.
Hard to apply (but this is inevitable - at least it doesn't need some liquid applying like some covers).
No instructions.
Apply as follows:
1) Clean every last smudge and dust fleck from screen using cloth (you may need to use a proper DVD cleaning cloth if your screen is very dirty).
2) Remove bits of plastic from screen cover's button cut-out hole.
3) Sit in a position that allows your hand to be steady as possible. Don't try this if you're tired or drunk.
4) Remove the bottom of the three layers and apply from the bottom upwards, rubbing the cover with cloth until whole item is applied to the top of the screen. If you see any bits of dust, remove screen and start with new one.
5) Remove top layer of cover, smooth down into corners and rub away any minor bubbles. Patience and persistance will remove most small bubbles.
6) If bubbles over touch surface cannot be removed, remove screen and try again.
My application on third attempt is not absolutely perfect, but as only very minor unstuck bit on one corner I decided to make do!