I'm not really surprised by that Piston score. I expected it to score somewhere circa mh1 though to put things into perspective my first pairs of mh1c cost me $15 and the mh1 I got months into the hype still cost me like $25, so I can't just say "WOW, I have never heard anything like this for only 20 bucks".
Of course, the Piston's hype got a little bit out of hand with stuff like being the best sub-$100 iem, being better than all vsonics and that probably raised some expectations a bit too high.
I personally wasn't too impressed but I acknowledged that I can imagine someone liking them a lot if that's the type of sound he's looking for. My main issue with them was the bass. which is exactly the opposite of what I like - slow, lacking control and proper attack.