Story - This is (obviously) a yaoi anime based on 2 main couples; a tutor flirting with his friend's brother and a teacher who falls in love with a younger guy. There's a 3rd one as well, but it's not quite as important. The first one, Usagi and Misaki, is really the more focused on of all of them. Basically, all the couples do is argue, get all depressed, and then have make up sex. Lather, rinse, repeat. That's the main conflict in this anime, in a nutshell.
Art - Um, to put it bluntly, the art sucks. In my opinion, the worst part of this anime. Seriously, Usagi's chin is awkward and boxy. It looks like someone took a hammer to it and then tried to fix it back to normal with their hands or something. I think someone already pointed this out, but the characters pretty much all look the same but with different hair and eye colors. Very boring designs. Needless to say, the art is absolute crap.
Sound - Opening and ending songs are garbage. Seriously. Background music was bland, didn't do much to enhance some of the more meaningful moments in this anime. Not much more to say about this.
Character - Here's where I'm kind of drawing a blank. The characters aren't bad necessarily... just not the best. They actually do develop, but still. I could predict their every action before they even made it. They're just plain boring. Not sure how else to put it. They're whiney, and the seme of the relationship seemed to be obsessed with exploiting the uke. Same old, same old. However, they have proven to have interesting interactions with each other on occasion. It is kind of amusing to watch the uke being taken advantage of, over and over again.
Enjoyment - Junjou Romantica wasn't all that bad. Repetitive characters, boring plot, ugly art, terrible music. It sounds terrible from how I described it, but if you watch it yourself you'll see that it's kind of a fun anime. It has a lot of issues, but it's still cute. It's entertaining, just not the best thought out show out there.
Overall - I know it seems like this whole review is just bashing JR, but it's not the worst anime out there. There's better, of course. JR just isn't an anime that you can really hate exactly. Yaoi fangirls, if you're looking for porn without a plot, don't watch this. The sex scenes in this aren't explicit, and it actually does have a plot (as lacking as it is...) If you like cute romantic relationships between 2 guys without much substance, then give this a shot. If you can stop staring at Usagi's hideous chin, you may even enjoy this. ^_^
