I have one, I really like it... I could imagine that given the right amount of heat+oils it would slip. I tend to leave the wrist rest on anyways as I have an external keyboard etc. It is not really designed to dissipate heat as there is always space between the bottom of the laptop and the stand anyways. It's advantage would be minimal at best.
All things considered I do like it and it does make a nice (attractive) lap stand.