I do not have much experience with different Android devices but I use the Samsung Galaxy Tab S2 and everything works fine for me.
I ve no connection problems. I use it in WLAN and even if the tablet provide a Hotspot I can connect.
It's quite hard to recommend Android devices with confidence. We know cases when pretty working device had problems after Android upgrade.
Usually all devices recommended by DJI (for DJI GO) will work also with UgCS.
I personally use Samsung A6 2016.