A long long time ago when I first started watching anime, I came across this and dropped it after the first two episodes because it was so hirribly, HORRIBLY annoying.
And yet, the rating for this anime is relatively high...
So, after many years I have decided to give it a nother try.
Although it's very hard to find a proper download (bad quality and subs are very bad), I'm watching now and am up to episode 8 and surprised to say, there's a lot more to it than you'd expect at first glance. Yes, Sana-chan is still extremely annoying, but she has her heart in the right place.
So, for now I'll continue watching and see where it takes me.