Having both 5.0 and 8.A I can tell you that, to me, there is a difference. Both sound good. To my ears the 5.0 has clearer separation and a more mid forward sound. 8.A has a more ... complete sound, richer. The lows are deffinitely lower for the 8.a and the highs are crispier. Both sound better balanced - don't hit me - they just do to my ears. You can't go wrong with any of them - they sound similar as general direction. It's iem vs ciem, price cs price and clear versus rich ( and clear
).
Hope it helps a bit - I am just trying to say it how I hear it. I am not much of a reviewer, in case you hadn't noticed