For the most part I liked Red Garden because the characters (well, most of them) weren't the same tired anime stereotypes that you see most of everywhere else.
*possible spoilers*
If I remember correctly I saw some inspiration from Romeo and Juliet because of the two struggling families and the love affair between two enemies.
The only part I really didn't like was the ending which clearly is an "we're out of cash already?"-ending. Well, either that or the writer just having no idea how to wrap up.