I don't know if its different for Plat members, but I call 800-450-4442, and then after typing or saying my Plat number, I hit 0. I've always (four times in the past week, at various times during the day) got an agent within 15 seconds. I use the agents to redeem some awards, ask questions, whatever. No problems here.

I've redeemed a 1 week stay over Thanksgiving at the JW Marriott in Hawaii w/o a problem. I had to be flexible because AA and US had blackouts and sold out (in award class) flights, but Marriott was available every seven night pair I checked.