I did notice a slight decrease in flaccid state only, corresponding to slight dip in the graph, but after initial swelling went away erect gain stayed constant. I really did not notice any difference in the way it felt going from filler to collagen. Felt completely natural the entire time.
I have not had HA, and avoided it for the exact reason that others had it feel "squishy" (not all, but a good amount of guys). Ellanse feels rock hard when Erect, no different from natural. I suspect this is the same for PMMA