A bit too small making it awkward to hold and play with. Useless back button placement, constant accidental presses. Clicky yet simultaneously mushy face buttons that don't feel as good as mechanical switches should. Only had it a night but but I can tell it's not for me.
The 3 best things are the build quality, configuration app and how smooth the thumbsticks feel for a "cheap" third party job. The official stock controller is better in almost every way in-game