Where to begin with this series? Well, let me just say it right out, whatever people might say, this show is not actually bad.

It has amazing production quality and some of the camera shots are Hollywood worthy. The main intro song fits the intro video really well (although I hated when they changed it later on because it didn't fit at all with any other song). And the premise of the story is interesting and fun too.

Now, why is it still so badly rated? Mainly because while the story started off well, it never closed. Over the duration of the series, probably around half point, the story got lost and while we do get a lot of fan service, we don't get much story development or even character development. The production was influenced by the worldwide crisis going on but the story had been lost even before that, so you can only fault the slightly rushed ending to the crisis.
As for the acting, it was okay. Some did better than others and overall there are some really amazing scenes and some awkwardness included.

Overall, WHY R U is a nice series to watch inbetween but you should not expect a fully fledged out story or Hollywood acting from it. The production gets the highest compliments though, the quality of the pictures and everything is just breathtaking.