I'vve had it since 2008....LOVE it!
I got the $200 bonus (in the form of 30,000 bonus points) and it is really easy to use the points. The best thing about it? If you use it as your credit card on file at WDW, your room charges are all considered "travel" since the billing party is the resort

. We recently went to HHI and used our KTTW card to pay for a dolphin tour, kayak trip, Kids Nite Out, several souvenirs, refillable mugs, a quick-service meal and some adult beverages and 2 bike rentals at the resort. ALL of it got charged to the room and our $500 in Blue Sky rewards covered it all.
UnderCoverTourist is also considered "travel" so you can buy discounted tickets with the rewards.
One thing to watch is individual transactions....they can't be lumped together. For example, I recently booked airfare on AirTran. I booked it as two one-way trips. My TOTAL airfare was $199.xx, but it was $109 and $90 segments. I still had to redeem $200-- $100 towards the $109 segment and $100 towards the $90 segment-- and I still had to pay the $9. (This would have been avoided had I booked it as a round trip). I find that when we plan on using the credits towards hotels, I am always looking for a hotel that is as close to $100 as possible.
I have everything I can auto-billed to the card. I use it as our primary card and our Disney Visa is the back up. As a PP mentioned, the biggest downfall is the fact that it isn't as widely accepted as Visa. They're customer service is outstanding and I love how the bill is separated into what is put on my card and what is put on DH's card, even though it is the same account.