I put a ZAGG protective cover on mine after about a week of use and I'm very happy with it. I use my SP3 to draw / paint and the feel of the stylus on the cover is very smooth.
Xtremeguard.com has both the wet install type and the dry install. Use coupon code summer85 for 85% off your order. I've purchased many protectors from them and overall have been satisfied. I purchased the SP3 protector and it fit well, but I screwed up the install with dust beneath the protector so now my SP3 is naked.