In my personal opinion, "Escape from Monkey Island" is the worst in the series. Suffice it to say that seeing the graphics of that game feels like a kick in the fundament. Really... all the persons in that game look like they were coming right out of the original "Alone In The Dark" game (you know... the one from 1992). In "Grim Fandango" that still worked because the persons in that game were skeletons and demons. It looked quite okay that way. But in "Escape" that just didn't work. Also the controls absolutely suck.
But there's something a LOT worse about that game: "Escape from Monkey Island" almost managed to ruin the whole Monkey Island universe!! It took the present day tourist/vacation atmosphere a step TOO far and almost ruined the franchise with pop culture/brand references. (Thank God, Telltale managed to re-ignite the spark of a swashbuckling adventure in "Tales"!)
Also LeChuck was turned into some sort of Sunday morning cartoon character – whereas before he was a frightening and unpredictable villain with strange voodoo (and/or ghostly) powers. After the ending of "Escape", one couldn't help but feel a sense of ridiculousness (as in: "hahaha *sigh* let's see what that droll LeChuck will be up to next"...

). (Thanks to Telltale he is a fearsome demon pirate once again!)