Can't comment on pros and cons of every program, but if you have Gold with Hilton but no hotel cards, then you should consider getting both no fee Hilton cards from Amex and Citi (no fee for the 1st year) for 110,000 points total. If you consider Starwood, then Amex Plat will give you Gold status which I personally have found very useful for getting an occasional upgrade (although I know many others on SPG forum would disagree).