I'm not enthusiastic about some of what has come out about the new merged program but like CPRich said, I'm not screaming the "sky is falling" yet either. When the merger was announced I was sitting on 1.1 MM SPG points. Since then I have stopped using my SPG Amex card and have used around 200k points. Since I'm in my last year of LTP qualification, I plan on qualifying for SPG Platinum this year to get me to LTP. Moving forward I will likely be more of a free agent for paid stays and work on reducing my overall points balance with Marriott/SPG.
In the end I think Marriott will loose a ton of Starwood elites due to a number of reasons. For me it boils down to them doling out Lifetime Platinum Premier to their members as well as the new devaluations on the credit card side. For paid stays I will be better off in the future upgrading my HH Amex to the Aspire card and getting 14 points per $1 spend while holding Diamond HH membership...than using one of the new Marriott Rewards cards and getting 6 Marriott points.