I enjoyed Oreimo Vol. 2 quiet a bit, but it shines a slightly different light on Kirino than the original light novels, and the Anime adaptation. I'm not sure why Dark Horse chose to add American slang, and swear words that weren't there into the translated series. They add nothing to the story, and mostly feel out of place.
As for the book itself, it is great quality. The pages are thick, and the artwork is well done. There are a few places where the editing needed to be better, the reader is left with 1/3 of the page blank, and a cutoff picture at the bottom; but it's unknown to me if this was done intentionally or was simply an oversight. If it was done intentionally then it seems out of place, and unprofessional.
I don't feel like the translation overall really does the series justice. While it's nice that 'Ore no Imoto ga Konna ni Kawaii Wake ga Nai' is getting an English translation, I feel like most of the emotions portrayed in the original are lost in the translation; mostly due to cultural differences. Still, I think it's good to support the project; I would still recommend that readers give the series a chance.
Some people have pegged the series as incestuous, not true (at the moment) and nothing incestuous happens in this mange, or the first season of anime. Can't say it won't change in the future, but it isn't happening now. It's just more of a brother, sister bonding relationship. Them coming to terms with who they actually are, and doing so with each others help.
This manga in particular follows the end of the first light novel, and the beginning of the second one. It is from the half-way point of episode 3 of the anime to the halfway point of episode 4. The manga doesn't seem to cover much ground very quickly, which is fine since it's not a story that needs telling quickly.
I have already preordered volume 3, due out on July 9th; if that's any indication of quality. I would have given Oreimo 5-stars, but the childish, English translation actually made me enjoy the book less. Hopefully those issues will be remedied before too many volumes have been released; it would be nice for Dark Horse to listen to the series fans on this one, I'm not the only one who thinks this way. There is a letter at the back of the book from a fan, they says practically the same thing about the slang and useless swearing.