Mine is a Tren/Prop mix, so that is a bit different. For me, compared to a tetnus shot, I would say that Prop seems to permeate the muscle a bit more. You may be onto a pretty good overall comparison though. I can't think of anything much better. Pain on injection for me is really insubstantial, but for a few days after the shot I notice moderate muscle soreness. It just isn't that much of a problem for me.