Kind of an odd pairing to talk about, but I'll make the link.
While reading Deathnote I kept seeing ads for Rosario Vampire. The cover girl looked cute so that got my attention. Got a couple of issues and this is pretty much what I found: Tenchi Muyo in a high school for monsters. Generally I find the story arcs are well written, but also repetitive. Big bad monster makes havoc, Tsukune makes the save by removing Moka's cross. Monster of the week would have gotten away with it if it wasn't for those meddling kids and their bat too. This is the same process for introducing all the main girls.
What has bothered me throughout the series is the high level of violence and blood that these kids find themselves in. The characters are 10-17 years old. Yes it's monster manga, but if it was a college setting, no problem. Then there's the sexual component. While I don't recall anything explicit, just the occasional hands on inappropriate places, shots of upskirts and bras, and girl with open robe on top of guy. Once again it's just the age factor. Especially with Yukari and Koko. Why? I really don't see the need to see these little girls in the situations that they put in all the time.
(What is it with witches in this series? Yukari is totally perverted at such a young age. Openly trying to get Moka and Tsukune in a menage a trois and copping a feel on a grown up Koko. Let's not get started on Ruby.)
I have considered many times dropping Rosario Vampire from my reading list. What keeps me coming back is the writing. While it doesn't have the depth of say Deathnote or the warm fuzzy of Inukami, it's good enough to keep me interested at least.
That's the important part. These characters are growing. They're not stuck in neutral like in Oh My Goddess. Friendships are formed and changed all the time. Most tend to have a deep emotional background as to their motivations. Even Gin. For someone that is hardly ever seen, he is really well put together, both physically and personality wise. That's why I tend to over look the violence and what some call fan service.
I digress to tell this story. A friend of mine has been buying this series for his son. I asked him if he even knows what is in Rosario Vampire. He said he flipped through just to make sure there was nothing he had a problem with. “Hey, it's not like it Hustler Humor.” He told me. He's right. As long as parents take the time to open up the book and see what is inside and not rely on the rather misleading jacket.
On to Girls Bravo. There was a sale at the many Hastings were I live. Buy two get one free. Plenty of Girls Bravo. How can I turn down a good deal like that with such cute girls on the cover? I thought to myself: “Self, you know what you getting into right? It's pretty clear on the covers and the rating on the back.” I was a bit wrong. I though there was going to be nudity everywhere. We get plenty of fan service and compromising positions. When after many volumes we finally get some nudity, it is rather uncleverly censored.
I only have four volumes. I doubt I'm going to continue with it. It's the writing. It's not good. Everybody is stuck in neutral and shoe horned into stories that are pretty generic. There is no growth what so ever. Not even in the outlier characters get much. In Tenchi the characters didn't do much, but at least we saw Yume and Minagi grow, change, and develop.
Now the anime of both series is the opposite of the manga. Rosario Vampire is not well written and not really well animated. Where as Girls Bravo was superbly written and animated. I had low expectations for the anime of Girls Bravo, I was completely blown out of the water. Everybody had motivation, direction, growth, depth, and well thought out character background. The manga's stories were contained within a single chapter. The anime's writers were able to flesh out each one into a twenty minute episode and make it entertaining.
However...
Both series have a problem: the over sexualation of the characters. While I could tolerate the poor writing of Rosario Vampire, I don't get the constant upskirts, Kurumu's much more explicit and has all sorts of sound effects, and Yukari even more perverted. Girls Bravo is a constant stream of nudity distracting from what was a good story.
Maybe I'm just being too conservative on that particular subject. Strange considering my mom let me read Hustler Humor when I was ten.