These documents are similar and are often used interchangeably. While they vary a bit from each other, they are used for the same purpose which is to show intent and an agreement to agree. Most are considered "nonbinding" unless the wording is included to make it binding.
You want your closing statement to be the Mariano Rivera of letters of intent: a clean win, effective, and unambiguous. Don't overthink it! Basic, professional closings are the way to go.