I use Sunshine Mix #4. It's a peat-based medium (so it should be treated like coco/hydro as far as water pH) that's inert, has good water retention and drainage, has Perlite mixed in, has great aeration, and is clean (I've never experienced bugs in the years I've used it). I buy it in 3.8 cubic foot bales for $35 CDN.
I veg for eight weeks and flower for 10. I plant in 1/2 gallon containers, and transplant to the final three gallon pots about four weeks before going to 12/12.
After a grow, I put the used medium in my compost bin for use in my outdoor gardens the following year.