My renewal anniversary date is coming up in a couple of months and I will be keeping it. For me, the cost/benefit ratio has definitely been worth it. I've taken advantage of enough of the perks to come out ahead even without considering the signup bonus.
I think there may be some non-advertised perks as well. I recently reserved a regular suite at the Washington DC RC and was upgraded to the presidential suite and it was, er, sweet. I don't think it was a coincidence. It was the first time it has happened and might be the last but it was a pretty cool experience. I also am a fan of some of the special opportunities they send me occasionally. The recent overnight stay at the RC central park for $500 (included dinner, brunch, art tours, etc.) was a pretty good deal and I hope they keep those types of offers coming.