ime, jiffy plugs are a pain in the arse for clones but work well for seeds. The bubble cloner roots like 90% and quite frankly the 10% that don't are usually clips that shouldn't have been bothered with. With that said, the thing with the bubble cloners is we all want the root structure that AERO cloners (from the pics we see) get, so there's a tendency to let them go to long. Clones that get accustomed to hydro (bubble cloning for example) don't neccessarily take to mediums when transplanted. Rockwool works just fine as long as one doesn't kill it with water or lack of and can pretty much be transplanted into anything. It just takes a tad longer ime than what most claim/post on the internet.