I am both MPlat and HDiamond (though MGold would suffice).

Marriott scores big:

1. Travel Package + All-Inclusive Package + transfer airline points when airline is offering transfer bonus.
2. EEO certificates (especially great for Sat/Sunday combo since Sunday night considered weekday rate)
3. Mega Bonus and Bonus Bucks offers fill-in during non-EEO periods
4. Circumvent no free breakfast issue by booking the S4B rate ($10 more for most Marriotts that I stay at)

Highlight #2 : Atlanta for Monday morning appointment combined with personal trip. I book Saturday $89 S4B at a full service Marriott Sunday night using EEO is free. If I had booked Sunday night only that rate is $199. I saved $110 plus had a full buffet breakfast.

Hilton scores big:
1. For family vacations, especially to Europe. Guaranteed Executive Lounge access whether upgraded to concierge level or not.
2. Free breakfast
3. Very successful with incredible suites
4. Love current bonus program 4x points