I used both because I didn't have enough of either one. Mel's Mix, from the book Square Foot Gardening, is designed specifically for raised beds, so 1 part peat moss, 1 part vermiculite, 1 part compost. No humus at all, so it' a very light, porous mix. I have 64 square feet of raised beds, 8 inches high. When I built them last year I only filled them six inches deep because a) that's what the book says, and b) that's all the compost I had on hand. I needed two bushels of vermiculite and only had one but since perlite is kinda similar I used that since I had a ton of it lying around. I plan to build a couple more beds this spring and since I have no materials left, I'll be using only vermiculite, not perlite. There's also a small percentage of hydroton in there from rootballs ending up in my compost pile over the years
I'm sorry you had to reassure me you weren't being judgmental, RIU has never been very civil but I don't play.