I agree. the Park Hyatt in New York is excellent. Stayed there for a work conference in May (even though I live here...lol). The corner suites are awesome and love the bathrooms there! Le Labo cosmetics are a nice touch too. Little harder to invite "guests" though... (depending on what they wear, they may get some stares...lol). I think Gramercy Park Hotel is nice as well and more neighborhoody and easier for guys to walk in and out....
I think most nice hotels are fine for hookups, just depends how much scrutiny they have and ease for your escort to walk in and out. Forget Aman resorts, the doormen memorize the names of all their guests.