So I realized I kind of wanted to discuss this. Because besides amazing characters there's so much more.
What seems to be your typical character-sent-to-another-world turns out to be a series that makes fun of that category.
From the start things are odd, the main character, Yuuri Shibuya (who is constantly made fun of for some kind of weird pun) is sent to another world. The way he's taken there may take you back a bit but it is very, very funny.
As the story continues your introduced to many characters, some of which are important and some that may not seem to be. However, one of my favorite things about this series is that characters that seem minor turn out to be highly significant. Later in the series you'll be left thinking. "I remember that, I didn't realize!" at how significant they are.
A extremely negative thing about this series is the animation. Most of the time it's just above terrible, the budget cut makes me want to cry at points and it goes from decent to really good to bad and all over again. Once the third season and OVA's come around the animation is alot better, and I know I'm not the only one thankful for it.
I can't rant all series plot, Kyou kara maou is full of shippings. Although it is shounen ai there are a handful of girl/boy pairings. Including a few of the main characters. There's enough for everyone to have their full of fanservice.
Although I'll have to stick with the royal family thank you ;D
All in all, it's worth a watch. The story does get serious but it is full of side stories and adventures. Comedy, romance and tension laid about it's a good watch. If nothing else, it's full of pretty boys.