Differences

Liquid.NET can group if expressions using parentheses, which is not currently possible in liquid.

    {% if (false and true) or true %}Result #1 is true{% endif %}
    {% if false and (true or true) %}Result #2 is true{% endif %}

==> Result #1 is true

You can negate an expression with not:

    {% if not false %}Not false is true.{% endif %}

===> Not false is true.