to gel or not to gel

I met a pretty knowledgeable corvette guy at the Sat Ecklers show.We were talking body work when he told me about e product made by Evercoat called "slick sand".He told me many body guys are using it in place of gel coat.Evercoat's website says it's a primer surfacer that has good adhesion to metal and wood.Anyone out there ever use this stuff?