I've seen the whole series (including HL Advance and HL Final, which havn't been licensced in the US yet)
The content stays pretty much the same through all the seasons. Their is one episode (episode 11.5 in the ADV release) that takes place at a hotspring so their is some fanservice there, about at the level of a Love Hina episode, but that's as bad as the show gets. Their were a few beach episodes too, so the moms are shown in swim suits and stuff. One episode of Advance featured a well endowed female theif who seemed to be a parody of Cutey Honey. Overall the show is pretty tame compared to most other "harem" shows (Tenchi, Love Hina, Mahoromatic, and Ai Yori Aoshi all have way more fanservice)
I think possibly the biggest problem people might have with the story is that *warning, MAJOR ending spoiler*
[spoiler] In the end Chitose ends up dating Mutsuki-mama. The age difference wouldn't really be a problem if they were just a normal couple, but the fact that she's his homeroom teacher and that she moved in with him for the purpose of being his MOTHER, not girlfriend, makes it rather creepy. Makes me think of all those teachers being jailed for having relationships with students. I also think having the two of them fall for eachother was extremly out of character and dumb -_- [/spoiler]
Overall, I really enjoyed the series a lot, especially the last few episodes of season 1 as well as Final episode 1. Everything was going perfectly IMO, and then it all just flew out the window in the last two episodes
. I hate the ending. I recommend everything up until HL Final episodes 2 and 3.