I have been both Hyatt Diamond and SPG Platinum (50) for a couple years, and I thought I'd share some thoughts...

- Starwood Suite Night Awards are *TYPICALLY* (i know people will come up w/ counter-examples) useless when you want them. I.E. You're taking your wife to New York, and you want a suite upgrade. You probably won't get one. I have had near 100% suite night failure at properties I wanted suites at: Sheraton Steamboat, W San Francisco, Sheraton Tribeca New York, the list goes on. However, I had an expiring night right now so I'm in a suite at the Sheraton Brookhollow Houston by myself right now... when I care about it least. I would go on the assumption that the SNAs just aren't very useful. HOWEVER, they can be applied to award stays. The Hyatt confirmed upgrades must be on paid stays, but they basically clear 100% of the time at booking.

- Hyatt points are great. Starwood points are better. Not only is Starwood a fantastic program like Hyatt, but you can also transfer your points at pretty lucrative rates to a bunch of different airlines. I would much rather have 500,000 SPG points than 500,000 Hyatt points. I doubt many would disagree with me.

- I do get fairly regular suite upgrades at Starwoods when I'm not expecting them. On the contrary, I typically never receive complimentary suite upgrades at Hyatts.

- Hyatt wins on the low end, assuming you can find a property. I *hate* Four Points by Sheraton. I really like Element / aLoft, but I can't stand staying at Four Points. I know there have been improvements, but I've stayed at far too many nasties. On the flipside, I love Hyatt Place / Hyatt House. The Hyatt Place breakfasts are REALLY good, and Hyatt House isn't bad either. I like the food options Hyatt Place has if you just want something quickly, and we're all addicted to those peanut butter cup cookies .

- On the high end, I would say it's close to a tie, but I like that Hyatt doesn't have any of the ridiculous "all suite" properties where they charge 2x the category rates. In fact, you can always get a suite for just a 50% uplift. The redemption rates are always reasonable. In contrast, try redeeming for something like the St. Regis Bora Bora or the W Maldives with SPG. The rates are so high that it's not really a good idea to do so. There are WAY more high-end SPG properties though, and many of them are in really exotic places like Mauritius, New Caledonia, Seychelles, etc. The only thing Hyatt has like that is the Park Hyatt Maldives. In terms of Park Hyatt v. St. Regis, eh I probably lean toward Park Hyatt, but there are way more St. Regis properties out there.

- The breakfast benefit w/ Hyatt is much better than the continental offered at most SPG properties.

In any case, hopefully that's useful feedback. I really like both programs a lot, and they have taken me from being almost a lifetime Marriott platinum to not really crediting any stays to Marriott anymore.