The ending turned into cluster after Ch.42. I've never read the novels, but it felt like this series was axed and the author had to rush the story through to the ending with those final 5 chapters.
But other than the rushed ending this was decent reading with a lot of fanservice and even some borederline Smut scenes every now and then.
If I had to compare the manga to the anime adaptation, I would say that the manga offers an actual story while the anime is all about "oneshota" fanservice. I'm not saying that the anime version is bad or anything, but don't let it to discourage you from reading this because the manga version is slightly different. =)
My verdict is 6/10 - It's a fine series and manga doesn't have to be 8</10 in order to be entertaining. =)
(if it wasn't for that cluster ending I would have given it 7/10)