Fake clicks - when I left click, I feel a subtle click on the way before actually clicking. Wireless connection horrible - stutters on wireless connection every once in a while. It makes it feel like my frames are dropping when in reality it's the mouse polling lag. Battery status does not update correctly or it just dies at 50%. Battery life is alright though. I have bought a Model D2, and received a replacement as well, it suffers from the same issues if not worse. I don't recommend buying from this company.
They have good customer support, but not good products. I regret buying this mouse.