It totally depends on what destinations you are going and what type of accommodations you are after.
For me, I'm a SPG refugee who has pretty much abandoned SPG, due to sub par properties in Hong Kong, Taipei, Singapore, and even Bangkok. Plus the new and wonderful Hyatt properties in Europe (Park Vendome, Park Milan, Park Moscow, Grand Berlin, etc.) and the luxurious properties in Asia (Park Tokyo, Grand Taipei, Grand Hong Kong, and Grand Shanghai), all of which beat the respective SPG property in the aforementioned cities.
Yes, SPG has a great presence in Italy and with those ornate European hotels, but at 20-something, I can't breathe in those establishments! Something fresh, and modern -- which is what Hyatt offers in most of its properties. Some may argue SPG has modern luxury in Westin and W, but honestly, the SPG W and Westins are more of a cookie-cutter type accommodations, and frankly rather uninspiring after a few stays. The W properties are even very susceptible to wear and tear, and I think the hotels don't maintain them as well.
SPG does better in giving upgrades to suites, but I have lost of cases when the promised suite upgrade does not materialize. OTOH, Hyatt will try its best to guarantee you an upgraded room, even if it's just a deluxe room. Try getting an "upgraded" room in the Sheraton Hong Kong, and the Sheraton Towers Singapore....
Also, with a guaranteed breakfast benefit, Hyatt provides more value than simply the "executive floor" benefit at properties without executive floors. At the Park Vendome and the Grand Hong Kong, a complimentary breakfast can set you back as much as $45.....
Also, the Park properties are more "fashionable" places to stay then the old stuffy SPG properties. Also, the FFN promotions in Hyatt are simply the most generous. I've taken friends and family for stay in Asia, Europe, Pacific, and North America due to this wonderful promotion. I have earned more nights than I could effectively use! Talk about generosity!
SPG, with the targeted promotions, always left me with something to be desired. The new free weekend promotion is hardly attractive after being so spoiled by the FFN. Once you've stayed at the Park Tokyo, Park Vendome, and Grand Hong Kong, you will wonder why you had even stayed at the Westin Tokyo, Prince de Galles, and Sheraton Hong Kong.
Lastly, the customer service reps at Hyatt are simply the best! I even had a gentleman named Chris in Omaha who remembered me just by checking-me in twice over the phone, asking me how I was doing and inquired about my stay at the Park San Fran last week.....amazing, considering the amount of callers they deal with every day! With Hyatt I truly felt like a valued customer, even when I was Platinum, since I progressed from Gold to Platinum to Diamond in a period of three month late last year.
Well, YMMV, so don't take my word for it. AFAIK, most FTer who switched from SPG to GP have been quite happy about the switch. Downside is there are no mid-range properties in Hyatt, and in smaller cities there might not have any Hyatt presence at all. However, if you travel to most metropolitan areas you should be fine (with a London Regency returning).
[This message has been edited by jkc22 (edited Feb 24, 2004).]