It is not bad, actually. The only problem I have encountered is that if you want to use the discounts towards tickets on LCCs, they typically will not do it. I could not, for example, redeem points for tickets on Spirit. However, there seem to be no problems with redeeming points for flights on majors. I recently redeemed points for a $400 discount on a IAD-CUR flight. I gave the agent the flight numbers on AA, and she cheerfully booked me in 5 minutes.

Even though the number of points you need is higher than on traditional mileage cards, the flexibility (you can choose between many airlines) makes up for it.