Qiang:
5090.8 DPS
1394 agi
2090 stam
705 haste
1059 mastery
Gao-rei:
4814.0 DPS
1317 + 500 agi = 1817 agi
1977 stam
892 expertise
856 mastery
320 crit
Honestly the agi makes Gao-rei win easily. Weapon DPS is nice for DPS, but does nothing for personal mitigation (would improve our raid Guard uptime but does nothing for us personally), whereas agi is a very nice boost in AP (Guard), Crit (EB uptime), and dodge (lol). The haste on Qiang's is nice, but not a deal breaker.
Gao-rei wins IMO.