Get-ADObject -Filter * -Properties * | ConvertTo-JSON > ADObjects.json
And you have access to ALL of the .NET library.
' "Here is an ampersand... &" '
To clarify, in PowerShell there is a difference between text between single quotes (e.g. '$test') and double quotes (e.g. "$test"). Single quote strings are literal strings, so whatever text is contained within them is reproduced as written. Double quote strings are expandable strings, which means that certain text inside the string is evaluated before it is returned. If you have double quotes in a literal string, you'll see double quotes within that string, and the same should be true for ampersands.