I stay at the Essex House whenever possible (I find the other *wood hotels in NY more than a little disappointing, esp. the W - talk about small rooms there, and staff with Attitude...) and have always been welcomed with friendly staff and excellent service.
Having said that, my policy has always been to take the view that upgrades are a welcome surprise and I have never (even when travelling with 2 kids and my wife all in one room) asked for an upgrade, and certainly never 'fought' for one like DCFFlyer.
The hotel's restaurants are very good and the bar has a nice feel about it.
I am sorry so many appear to have had bad stays there, as it would always be my first choice for a NYC hotel.