I really like this mattress protector. I got it to protect my new foam (imitation Tempurpedic) mattress.
I haven't tested it's waterproof-ness, but don't doubt that it would stop a spill or accident from reaching the mattress, at least until you threw a towel or something else absorbent on top of the spill.
I like the material of the protector. It's soft without being plastic-y. I definitely have NOT noticed a crinkling sound or plastic sound when moving around on top of the protector, especially with the sheets on top. I also have not noticed that this protector makes our mattress hot. (These were both big concerns for me.)
It seems like the material of the protector is breathable. It's also really soft and definitely doesn't feel like plastic -- I could see the potential for really soft or silky sheets to slide around on top of the protector, as some other reviews complain. But I use 100% cotton sheets and haven't experienced this problem. Would recommend!