I subscribed to the premium service and was able to quickly see domestic upgrade availability for some flights I have to do this week. Easy. One of the flights I had planned to take hadn't released upgrade inventory yet. I was able to find an alternative flight and immediately book it and get my upgrades (this is on a sometimes hard to upgrade DFW-DCA flight where there are a lot of first-class and Y fares). I also was able to find out C availability for some flights I want to use my VIPs on.