This is a show from the mid 2000s that would encapsulate the whole ecchi genre at that time. Story is much better than the OVA , the OVA didn't have a story . Animation is pretty good for it's time,at par with K-ON sometimes.Sound could've been better, especially the bgm. Characters, diffrent to say at least, but refreshing.
On a Personal note,no one should get tricked by the scores for this anime as it's probably gonna be more enjoyable than most of the shows airing today. I'm not kidding here. The OVA came out first, i guess they learnt what worked and what didn't and what you'll see in this show is perfection. The ecchi part in other ecchi shows sometimes just feels forced or makes you rethink your lifes decisions up to that point, however that does not happen with this show.It feels wholesome,i don't suppose that's possible with an ecchi show but here we are.
Show answers the question of the mc choosing 1 out of the infinite harem by saying , why have 1 Nee-san, when you can have 2. Why just stop at a loli kohai, when you can get her Nee-san too who also happens to be a sensei and why stop there when you have the morale of kanetsugu sama and become the new harem warlord of the high school you're entering[you wont get his until you watch a certain part of the show].Other redeeming qualities such as a Standard MK I. Ara-ara worldwide Oppai Nee-san,but she looks like an imouto instead of a Nee-san while still being the...wait what was i trying to say here? oh yeah, the shows pretty good. go watch it.