Never tried this service, but is it possible to parse the output of these rumors with a computer program? How close is the rumor transmission time to the time of the move? I'd trade it, if my computer can get me in and out for a few cents, otherwise I wouldn't touch it -- mostly because there are people with better computers and better networks probably doing the same thing.
jr07: Regarding rumors, I frequently scroll though the Dow Jones newswires, and have seen some "juicy" moves, as you described. Sometimes playing the second 5 min bar (if you're lucky to see it that early) can get you a few more bars if you're quick to the trigger and sell on the fourth or fifth bar. I've also seen it fade the whole move up and take everyone out, again, just as you described. Usually when you see it on the newswires, someone has already placed huge orders and are selling to YOU! Therefore, I usually play when it's a rumor on a stock that I frequently trade. If you simply buy or short a rumor on any random stock without knowing how it trades, you'll eventually get burned. Hope that helps...