I had RJD at #10, so not too far off the forum consensus. For me, his voice is that of the godfather of metal. Really just lived and breathed it. So happy I got to see him once (fronting Heaven and Hell) before he passed.
As for Steve Perry being this high and being my personal #2, I'm going to stay this again, like I said with Layne Staley - Steve Perry is an absolute master class on how to sing. If you are a singer, or know anything about it, Perry's technique was generally flawless. Incredible range, depth, control, it was the gold standard for rock singing. Period. Very few could be as consistent as him, both in-studio and on stage. There's one other one who did it the entirety of his career as well, and I think he'll be up soon, so I'll wait to say something. But if you're not really familiar with Steve Perry and his work with Journey other than the hits (and now you hear them not with Steve's voice, but with Arnel's since Journey re-recorded the vocals with Arnel and shops those tracks out to commercials, TV shows, and everything), do yourself a huge favor - go listen to the records...particularly the Live in Houston from the Escape tour. Perry didn't have to do any vocal overdubs. Then get back to me. CRAZY good.