Well, I receive compliments for my CSP all the time--it's beautiful. Sorry, could not resist.
OK, your question is like which is better an apple or an orange. Here is my take.
The best single hotel card is neither Marriott nor Hilton. It's US Bank Club Carlson. If you only want one hotel card and their locations work for you, I wouldn't look any further. You can find award locations around the world with this awesome website awardmapper.com.
Not mine (I wish).
If you insist on Hilton vs Marriott, I would suggest Hilton simply because there are so many credit card products that will allow you to manufacture hundreds of thousands HHonors points when you're especially bored. Hilton is very good if you do not insist on staying at the most luxurious properties in the world (if you do, it's bad).
If you have an extra space in your wallet, though, I would grab Hilton and SPG or Hilton and IHG before Marriott. Just my opinion. The list below is my take on
worthy hotel cards (very subjective!).
US Bank CC
Citi and Amex Hilton
Amex SPG
Chase IHG
Chase Fairmont
Chase Hyatt
Chase Marriott