Currently using mine without any issues - it's between the phone and my thin Spigen case. I never use the S-Pen on the mount - totally pointless...so this whole thing is a moot point unless you use a desk stand magnet holder.
What the metal piece will do, however, is interfere with wireless charging if the charger's coils cannot touch it well enough. I'm currently in the testing phase of seeing which charger works best with this setup.
Choetech Fast Wireless Charger 1:
http://amzn.eu/169eOGi
Choetech Fast Wireless Charger 2:
http://amzn.eu/4r62fmZ
UPDATE:
So I figured out a way to get the phone to charge with the metal piece inside the case to avoid the coils. Basically, place it horizontally near the bottom 1/3 of the phone (I had it in the middle vertically before - and this is the main area where the coils touch to charge).
I tested with both Choetech chargers this time using a good thick micro-usb cable to my Samsung Note 8 charger. I used the Ampere app to measure the mA. Charger 1 hit around 830-900mA consistently. Charger 2 hit around 500-800mA inconsistently. My Huawei Mate 9 Super Fast Charger and the Samsung Note 8 Charger with my Huawei Mate 9 usb-C Cable and Note 8 usb-C cable both hit 1030-1040mA consistently max when plugged in.
I'm returning the new one (Charger 2). It has a less appealing, odd shape with fans that don't really do anything. It's much bulkier too.
Normally, wireless charging is terrible compared to USB charging, but this setup really impressed me. Try it and let me know what you guys think.
