Formosa's reputation for good food comes from the previous owners Mai & Vong. The new owners are less than personable and their food lacks the exciting touches & attention to detail from the previous owners.
The menu is unchanged which is one bonus. I was recently there on a Saturday night, (a day when it used to be packed) we were the only ones in there. The food was better than average but the service was not.
Either way it's still be best Chinese/Thai food available on Plainfield.