I have one of those. And while I prefer Vise-Grips, the Cman actually seems a little heavier. I never used it in high-temp conditions, so I cannot comment on that. For $15, you really cannot go wrong. If it melts, take it back and get a new one!
Just don't buy those stupid laminated/riveted Cman locking pliers. Whose idea were those things anyway???!!!!