fives months of moderate usage and the factory-fitted screen cover is now visibly marked, but if I turn the back-light off it's not too bad. I'm about to buy a proper screen protector for it.
I've always fitted SPs to my handhelds - palms, zauruses etc. they're a silly price for just a sheet of sticky-backed plastic, but you'll kick yourself if you don't fit one. Wife has a palm tx and didn't bother, and she's got a nasty biro mark in the middle of her screen now. sigh.