remodel bathroom. HElp on insulation. FL

I just remodel my bathroom and im on the insulation, i had unfaced insulation with a poly (vapor cover) my question is HD is telling to use (RMAX i think what its called) instead on insulation and the poly stuff. I have a concrete house and the bathroom is on the concrete wall. so my insulation going to go on the concrete. What do i use? Please help!
Palm bay FL.
Whats the best way?