MSPeconomist

While I don't travel with family, I have several years as both SPG Plat50 and Hyatt Diamond, plus one miserable year as PlatMinus with almost no Starwood upgrades.

For me, a big advantage to SPG is that you can use SNAs or get free Plat upgrades even on nights paid with points or free certs. These also count for night and stay credit.

Hyatt doesn't count free (points or certs) nights toward elite status. I think that their new version of points and cash do count; at least Diamond suite upgrades can be used on these (but certainly not on free stays) as well as most AAA rates etc. Using points for a suite upgrade requires close to a rack rate.

For either SPG or Hyatt suite upgrades, you must check that you will be upgraded into a genuine suite and not just a junior suite, which can mean a slightly larger room with a sitting area.

Hyatt treats me very well; with SPG, it's been mixed. For me, a huge difference is having a wonderful Private Line Agent from SPG (although that program is being cut back), versus not being able to even get my own Plat Concierge from SPG or find someone that I would like to regularly work with on an informal basis. When the Abassador program expanded, it seemed to me that the quality of Plat Concierge service declined. (I had some dreadful experiences, even with Plat Concierge supervisors, both of whom didn't seem to even know the basic SPG program rules.)