According to http://forum.mikrotik.com/t/anybody-ues-at-t-gigabit-fiber-with-mikrotik-routeros/121679/1 both the RB4011 and CCR1009 perform well bypassing an AT&T Gateway.
You’ll probably need a BGW210-700, though. The Paces have issues with keeping EAP connections alive and require constant pings on other solutions. See if you can get your Pace swapped with the BGW210.