I was looking on the Grand Slam sub-forum yesterday, and some posters believe there will be no Grand Slam this year. Take that with a grain of salt, of course. But anyone hesitating on this offer in anticipation of another Grand Slam club offer may be disappointed.
When I bought my membership last August, the offer was for 3.5k preferred miles for (I believe) the same price. I'm happy to take advantage of a better deal this year!