The DC area is good for Hyatt. You have 3 suburban FS properties in Fairfax County and another two in Arlington and Crystal City. I am well known by a couple of the guys at the Fair Lakes Hyatt, and I have a better than 50 % chance of getting suite upgrades (without using the suite certificates) for one night stays. Hyatt has also been expanding the number of SS and HP properties in the area (mainly HP). Room rates are fairly good for Hyatt Dulles and Hyatt Fair Lakes, usually under $190 on weekdays and under $80 on weekends with AAA code. Hyatt Fair Lakes is sometimes as low as $58.65 with AAA on the weekend.
Hyatt and SPG FS properties have stricter cancellation policies than Marriott FS properties. You cannot cancel day of arrival, although some FTers have found ways around this.
Hawaii awards are better with Hyatt versus Marriott b/c you get breakfast and internet included (although some Marriott properties will include a refrigerator for free which Hyatt does not). Marriott has a larger presence in Europe than Hyatt, but Hyatt has a few gems in Europe: PH Hamburg, PH Paris, and the Churchill in London. Hyatt is strongest in Asia for international properties: you can find a property in Taiwan and New Zealand where Marriott is absent.
The current FFN promotion with Hyatt is quite nice since it includes stays that count double towards elite status and runs through the end of January 2010. If I were you, I would fax Hyatt a copy of your stays with Marriott ASAP. With this promo, you could easily keep top status with Hyatt, Marriott, and SPG.
Hyatt awards mainly come from FFN/bonus point promotions, diamond welcome gifts for points in North America (1,000 points at FS properties add up quick when the top award is 18,000/night), G & A bonuses for Hyatt points and airline miles, respectively, and occasional airline mile promos like the recently ending one this quarter with several airlines where you get an extra 2,500 miles for every 2 stays credited to an airline. Hyatt does most of its airline promos with United, and the upcoming one will run through Jan 31, 2011 and gives United elite members an extra 2,000 miles for each stay over the 500 base miles. You cannot collect a G bonus if you take miles for a stay, but you can take a diamond welcome gift and take miles (although you will have to call to get the diamond gift to post properly).