neuron

Agree with most of 365warrior's comments. While Hyatt has a much smaller footprint, the treatment of Diamonds far exceeds my treatment as an SPG Platinum (3rd yr for both).

I think the Hyatt hotels are generally nicer, the HPs are nicer than the 4P for sure and I prefer the Andaz over Ws, PH over St Regis/Luxury Collection. My opportunity for complimentary upgrades at Hyatts have been more freq than SPG. I also like the fact they have partnered with MGM Resorts/mLife making earnings easier. If you go to Vegas this may be a big plus.

I don't count on SPG upgrades to better rooms or suites anymore. They may have a policy of upgrading Plats to the best room, but I often have to cite this and always get the "reserved for someone else" or "room not available" line. I have called SPG at times to clarify, but its not worth having to argue for a stated benefit.

Now some good stuff about SPG - more hotels in more cities. Their points are more valuable for redemption (like converting to airline miles with a 25% bonus at 20K). If you are a DL flyer, you may like their partnership. They do have a lifetime Gold and Platinum offering beginning at 250 nights and 5yrs of Elite status. Also, stays incl free nights making gold or Plat easier, not to mention the getting the SPG Amex card that already gives you 2 free stays and 5 nights. Finally, if you combine all your nights and are close to 50, you may consider whether its good to split the programs, or stay with SPG to get to 50 (and 10 free suite nights guaranteed).