I've seen so many different methods of transplanting, but I think most of it depends on how tightly root-locked your plants are. If you're transplanting a lightly rooted plant, I say don't even mess with em. If they are rootbound and spun around your container semi-tightly, I would go with Chris Scorpio and crush em up gently. Tight root locked plants, I have seen people cut them top to bottom every quarter way around the soil about an inch deep. I am too scared to try this method, but the videos I have watched are from reputable dispensary growers so probably not entirely bad, but I bet people would disagree with this method. I tend to just go with Chris Scorpio on this one too.
I treat them like I do a garden, nursery bought tomato and gently remove from container upside down, squeeze and break up the root ball and soil and then gently insert them into their new home.