Waldorf is under construction, they were even jack-hammering while I was getting a massage... Disruptive with crap service recovery. I love the Waldorf location, however... far better for shopping and restaurants than Trump/Langham.
The Peninsula is a classic, yes... but stuffy and rooms are small with meh views. The spa, service and dining are most redemptive.
Ritz is being renovated now and has always had killer views with larger rooms/suites. I'm looking forward to checking it out post-renovation as they are opening a club lounge, too.
The Langham is modern set supremely tranquil, Club river suite is the way to go.