If I can add my two-penn'th:
I installed one of the 3 screen protectors that came with the A701 - annoying that they are about 2 mm too short! I installed my uppermost, so that now the stylus sometimes runs off the protector at the bottom of the screen. Oh well.
Also, I find in high light the addition of the protector does cause a slight 'polarizing' type effect i.e. makes it more difficult to read the screen, but only when screen brightness set to the first or second bottom position.
When you use the phone, the skin impression from the side of your head makes more of an impression on the protector than on screen without protector (tasty, eh?). I keep find myself rubbing it clear. Perhaps I should wash my face every hour when out & about
I have not had a problem when using single handed, although a lanyard boosts confidence - always feel I am about to drop it.