Check out these threads in the Hilton forum:
http://www.flyertalk.com/forum/Forum57/HTML/004745.html
http://www.flyertalk.com/forum/Forum57/HTML/006506.html
http://www.flyertalk.com/forum/Forum57/HTML/006632.html
http://www.flyertalk.com/forum/Forum57/HTML/007132.html
And these in the Marriott forum:
http://www.flyertalk.com/forum/Forum63/HTML/002161.html
http://www.flyertalk.com/forum/Forum63/HTML/002405.html
Some of these threads also offer comparisons of elite level benefits, which is important to consider in your choice.
My travel pattern and experiences make me a Hilton fan, however everybody has different travel patterns and/or expectations from a program, so you might be better of elsewhere. Nobody can answer your question for you...
BTW: did you consider Starwood? Many comparison threads on Starwood vs. Hilton or Marriott can be found on the respective fora.
Welcome to Flyertalk!
[This message has been edited by ql2112 (edited 04-11-2003).]