I own both, and hands down prefer Hilton. A few quick examples why...
There are so many more options with Hilton. I don't even think about my home resort with Hilton, which I will be staying in for the first time next July, after 3 years of ownership.
The last post referenced that new resorts require more Hilton points as a negative, but also mentioned that if you have less than a choice Marriott week, forget about exchanging into a choice Marriott. At least you CAN make a reservation into a newer/better Hilton... all you need is the necessary points and you are on equal footing.
If you have 7000 points, you can deposit about half with RCI and stay a week, take the rest and still stay for a week or several weeks with Hilton, depending on how you use them. I own at the Waiohai and, as far as I know, that is about as choice as Marriott gets. What do I get for it if I don't want to stay there, one week somewhere else. Granted it can be a prize week somewhere, but it is still just a week.
They both have conversions into their hotel rewards programs and, in my opinion, both conversion ratios are wasteful uses your week.
I don't understand those who say Hilton has limited locations. Here is the list...
Hilton Grand Vacations Club Resorts
Orlando, Florida
HGVClub on International Drive - Orlando
HGVClub at SeaWorld International Center
Las Vegas, Nevada
HGVClub on the Las Vegas Strip
HGVClub at the Las Vegas Hilton
HGVClub at the Flamingo - Las Vegas
Hawaii
HGVClub at Waikoloa Beach Resort
HGVClub at Hilton Hawaiian Village
HGVClub at the Kalia Tower
Kings' Land
The Grand Waikikian
Miami Beach
HGVClub at South Beach
Hilton Grand Vacations Club Affiliated Resorts
Ft. Myers Beach
Seawatch On-the-Beach Resort
Captiva Island, Florida
The Cottages at South Seas Resort
Harbourview Villas at South Seas Resort
Plantation Bay Villas at South Seas Resort
Plantation Beach Club at South Seas Resort
Plantation House at South Seas Resort
South Seas Club at South Seas Resort
Hutchinson Island, Florida
Plantation Beach Club at Indian River Plantation Resort
Marco Island, Florida
The Charter Club of Marco Beach®
Club Regency of Marco Island
Eagle's Nest Beach Resort
Sunset Cove Resort
The Surf Club of Marco
Sanibel Island, Florida
Casa Ybel Resort
Hurricane House Resort
Sanibel Cottages Resort
Shell Island Beach Club Resort
Tortuga Beach Club Resort
Hawaii, Big Island
The Bay Club at Waikoloa Beach Resort
Breckenridge, Colorado
Valdoro Mountain Lodge
Cancun, Mexico
Fiesta Americana Vacation Club
Los Cabos, Mexico
Fiesta Americana Vacation Club
Inverness-shire, Scotland
Hilton Coylumbridge
Royal Deeside, Scotland
Hilton Craigendarroch
Perthsire, Scotland
Hilton Dunkeld
Carlsbad, California
The Grand Pacific MarBrisa Resort
Portugal
Hilton Vilamoura Vacation Club