Saw all of it, too. It had it's moments but in general I found all the characters more or less annoying. I've had my share of stupid main protagonists in Harem-style anime, too. Seriously, I can't stand them anymore...
Of course Louise is a little devil/angel depending on the situation which made it quite enjoyable at times.
Anyway, I seem to have rated it with a 7/10 (which means good) on MAL. Maybe I should reconsider, thinking seriously about it, but it won't be fair without watching it again because it's been quite a while ago, me watching this.