I used to get good results from Pro-Mix actually, especially with a little added perlite. I found it to be cheap and easy and Menard's always has it. Then I decided since it was mostly inert anyway I might as well try something completely inert. So I tried perlite with a little vermiculite, in a recirc drip hempy SOG setup first, because I wanted something clean and simple that I could mostly automate. That worked well, but I moved on to straight perlite (first GPS run soon, hopefully!) because the verm was unnecessary.