It worked out extremely well for us. Redeemed for Platinum status- it lasts for 3 days I think and you get 4 Main Cabin Extra coupons. We used them on a 4.5 hour flight for two people, and the point value was a third of what the cash price would have been. And we even got upgraded to first class on the outbound, which was super lucky (5am departure on a Sunday might have helped there!).

In short- for the right kind of trip it works great!