I think a stiff bristled brush works better with hot, I'm getting great wear out of my Xteme medium mixed brush at the moment
well over a year, but I'm wondering is it a fluke as some find this very hard to believe.
Have tried the xtreme soft but it lasted no time and the xtreme stiff just didn't give me the confidence that it was doing the
job as when using it with cold it didn't have a great bristle splay.