As the guy that posted the first post... I think that I may have ben asking a question that didn't require a "VS.", my question was more of, from my perspective as a newbie, "I know that members have only used rotary's and though they know that OP is available, and they probably use it too, along with HWE... is there a situation in which a 175 comes on top? I knew that there might be, maybe. Otherwise the rotary/175/bonnet application wouldn't still be so popular. I was thinking T&G, but I've seen situations where bonnet "padding" did great work. Actually, I have learned through this, and I'm learning, that I was asking a question that was effecting too broad an answer in the biz. I believe that as HWE is to OP... so is OP to Rotary... it's, I know now, all about using the right application, with the right chems, with the right equipment. If this isn't a science... I don't know what is?