I had been mulling the credit card thing for the past year and recently went with the Chase Sapphire Reserve. The others in the running were the Amex Platinum and the Ritz.
The nail in the coffin for the Amex was the annual fee of $550 + $175 for my wife. The CSR is $450 + $75 which is easier to swallow, although I truly believe that charging for a second card on the same account is absurd no matter what the card is.
Anyways, I'll tell you why I went with the CSR based on my requirements:
1. 3x points on travel and dining. That's a good chunk of my spending (dining) when I'm on the road...which is a lot.
2. 1.5% point redemption value. I use all my credit card points on hotels and that sort of thing for vacations.
3. Priority pass select for all cardholders and no limit on guests. I think platinum allows 2. This is important for me appx. twice a year.
4. The lower annual fee vs the Amex plat.
5. $300.00/yr gets wiped out for all travel related purchases. Amex offers $200 for airline specific charges and $200 uber. I rarely use uber and as a non rev I don't pay to check bags etc. typically. So the $300 basically wipes out most of my annual fee. Not the same with the Amex platinum (this was a big factor).
That's pretty much it. The only downside to the CSR vs. the Amex is no hotel status. It would be nice to get some Marriott lounge access for free breakfasts as United keeps us in a lot of Marriotts, but I'm a west coast guy and most of my layovers are east coast, and I'm usually asleep past the lounge breakfast hours which IIRC, end pretty early.
The Ritz benefits are a little more vague. You get only 2x points on dining and travel, but a 10% bonus at the end of the year and it's hard for me to compare value that way. You get Marriott status, but the $300 annual travel credit appears to be more restrictive. It's possible that it is worth it so you may want to take a closer look at that one.
Good luck.