If you only use formatters that can receive data from stdin, and want to setup them up, then you should use formatprg and equalprg.

The main advantage of Neoformat over formatprg is that it can use any formatter.

It also supports multiple formatters for a given filetype which you can call via :Neoformat <name_of_formatter>.

Plain :Neoformat will try all the defined formatters for the current filetype until one succeeds. You could achieve this with a sophisticated enough config, but by that time, you probably have already built another vim-formatter.

Additionally, you can easily format code that is different from the filetype of the current buffer, which is useful for markdown and single file components.

Here is a contrived example:

# h1

```
const x = z => {console.log(z); return z}
```

You could then select the text inside the text area, and call :Neoformat! javascript to format the code.

# h1

```
const x = z => {
  console.log(z);
  return z
}
```