So we both bought them and for as cheap as they are they seemed to work great today. I dropped mine in the water of my footwell completely submerged for a few seconds before I realized it was there. Hah! The real time rate isn't super fast, but does it fine enough. Also there's a way to view the max RPMs and it stores it until you clear it. Making it easier to watch where you're going while tuning. Used it to tune my hard jet today and it worked great.
My ski has never accelerated so well and hits pretty good if you hammer on it.