I got BPI-R3 complete package for about 1 week, here is my personal quick review.
Antenna: Fair. speed drops slightly 5 meters away without obstruction.
Case: Perfect fit. Some people complain for no ventilation holes, put a laptop cooling pad underneath and problem solved.
Openwrt: Official installation/image had issue with transfer image to EMMC. I compiled the Openwrt snapshot image and the installation was pretty easy by copy SD image to every other storage.
Performance: iperf3 LAN to LAN = 950Mbps+, iperf3 Wifi AX to LAN 850-900Mbps (within 2 meters)
Openwrt open source wireless drivers worked out of the box.
I use it as my main router at home, I only need 802.11r, mac filter, SQM, USB storage. No additional features are necessary for me so not tested.
