Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.1030 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)
It really depends on what you value most out of an FFP. What class of service do you normally fly on paid tickets? Where do you want to go on award tickets, and in what class? How important to you are things like free checked baggage, free lounge access, free upgrades, etc.? How many (paid) miles do you fly per year?
Without that info, it's tough to make an informed recommendation.