There's a rare time that you come across a manga that deals with such indepth problems as racism and sexuality in well... such a unique way.
Knights pulls this off with off an aplomb with its engaging story and characters however. It caught my interest instantly with its unusual plot description; and kept a good, tight hold with pretty, detailed art and its handling of the unusual setting.
Saying that, it does fall to be quite generic in some places. There are characters that are predictable and while the art is quite nice, as I said before, it's still nothing special.
Overall, I'd recommend you read this manga.
I can guarantee it will have you laughing in a few places, and have you turning the pages rapidly otherwise.