Stayed Fri and Sat this past weekend with my wife. Was there for an all day business meeting on Saturday and some fun in NYC.

Very pleased with the Essex House. While not as nice as our usual luxury choice (Four Seasons) it's less expensive in a great location. I got us a Park View Queen for about $490/night through my travel agent, but my business partner booked through his AMEX Plat for the same price but was upgraded to the Park View Suite, + cont breakfast and $100 credit. We had the same amazing view of Central Park.

Here's my list of pros/cons for you to consider.

Location - best in NYC; close to shopping and sights; closer to Columbus circle (Per Se, Masa, Jean-George); walk to Lincoln center, Broadway, etc.
Rooms - I liked the renovated style, my wife hated it; modern/art deco with soothing colors; everything in good working condition but some small signs that it's an old hotel, like the rooms on the lower floors have very small windows (avoid if going for Park View)
Service - fair; not 4S but close; not personal but this is NYC; terrible touristy recommendations by the Concierge o/w no complaints with the other staff, but not memorable either
Food/Restaurants - expensive and not worth it. I don't mind expensive (ate at Masa and Jean-George this trip) but I want something special for extra money; $33 for cont breakfast + $5 delivery + 18% auto gratuity...for fruit and a pastry. For breakfast the short walk to Bouchon Bakery was far better. There's lots else in the neighborhood. They added gratuity to the restaurant bills but it wasn't obvious until checkout.
Other - they have a hotel car that will take you up to 10 blocks for free (but not pick you up); Signature booking gives you same amenities as AMEX Plat (but I didn't realize until returning home)

Verdict - for Central Park South the price/quality/location/experience equation works out in Jumeirah Essex House favor when compared to other CPS properties. Would stay again if the equation stays the same (but book with Signature).