Myopia and Essex seem to be 1 and 2 or 2 and 1 depending on who the rater is.
Some feel Salem is better than both...
The three compliment each other very well actually, as Myopia's course generally represents 1900, Essex 1915, and Salem 1925.
I would think that Myopia would get the common rater nod due to the difficulty of getting on, and the fact that it is a ridiculously unique and strange place. If ever there was a real "Mayflower Club," it is Myopia.
I'm on record as liking ECC the best out of the three, as a great meld of architecture, strategy, history, and playability, but we might have to go to hundredths of a point to set them apart...
In comparison, Myopia's weakness is probably playability...although it is one of the best match play courses in the country with all the great half-par holes. Salem is a longer, more "championship" layout, and probably more fair than both MHC and ECC. It's greens are the highlight, and they are representative of a more developed mid-career Ross style. Salem's "weakness" is not really anything to do with the holes so much as its setting being a bit less inspiring than the open-air formats at MHC and ECC.
Of course the joke of it all is that this is like comparing three bowls of the best ice cream you have ever eaten, just with different toppings.