I use a cheap UV filter and I still don't notice it. My Chinese knockoff set also came with a pair of ND filters which I haven't used much. But so far, so good.

I dunno. Looks a'ight to me.
I've definitely been grateful for the times when I've had crap flung me or my camera by the wind, animals, or often enough also nearby inattentive tourists. It's also nice to be able to just unscrew the thing in order to handle it when you need to give it a thorough cleaning. Walking around with your lens cap on all day to "protect" your lens is mostly just a great way to miss the opportunity for shots.
