With Citi nerfing the Prestige, and AMEX raising their Platinum AF to $550 just to add in Uber credits and 5x on air, I would say the Reserve is the best of the three unless you're routinely staying at hotels 4+ nights a time.

Centurion Lounges are found at a select few airports, $200/year in travel is only 66% of what Chase offers on the Reserve, Visa Infinite acceptance is 30% higher than AMEX, primary rental insurance is better than secondary, with AMEX your 5x hotel points can only be redeemed through AMEX travel, both have the $100 TSA credit, and the Sapphire Reserve is still $100 cheaper per year. Chase also offers trip delay/cancellation insurance whereas AMEX doesn't have either. Points also post at the end of the statement of the CSR whereas there's an extra statement lag on the Platinum. The UR portal also has better partners (even though I don't use any of them) such as Hyatt, Marriott (yes I know there's a work around for MR points, but that's besides the point), Ritz Carlton, Southwest, United, and Virgin Atlantic, all at 1:1.

AMEX is afraid of the Sapphire Reserve. That's why they added 5x on air and hotels, changed the material to metal, added Uber credits (worthless), and raised the AF.