Sailor Moon as a story: If you've read the first 6 books, obviously you'll want to finish them! Do not read these without reading the first ones. It is not a story you can just jump into.
Translation: FINALLY! Why did it take until 2013 for a reasonably good translation that stays as true as possible to the original?! There are some parts where the translation reads a little odd, but it makes enough sense. I also really appreciate that the translators wrote Translation Notes for each book, where they explain the different ways they could have translated a word or explain the full meaning of something. Naoko used quite a few puns that only make sense in Japanese, and those puns are explained well (such as Tin Nyanko's entire name being a giant pun.)
Quality: Many people complain that the paper quality is not as good as the individually published books. This is true, but in all honestly, it's not a big deal! The pages are not flimsy, they're just not as strong as the individually published books. Yes, the books are also slightly smaller. If superior quality is what you care about, then buy them individually. If you just want an economical way to buy the entire Sailor Moon manga, then buy this set! The only complaint I have is that there were a few pages where the print job was obviously lacking to some degree, because if you looked really close you could see faint detail that should have come through a lot better.
This version compared to 90's Tokyo Pop/ Mixx Comix translation:
Mixx Westernized the series as much as possible. They took out all the Japanese (even faint Japanese on building signs in the background.) They flipped all the art so you could read the story from right to left, like a normal English book, where as Japanese reads the opposite (left to right.) They gave all the characters the same names as the Canadian dub of the Sailor Moon Anime did (they did not have a habit of doing this with other series, like Magic Knight Rayearth, where the Anime dub left the character's names the same.) Basically, long story short, Mixx copied the English dub perfectly, and the English Dub drastically changed the Anime. While the quality of Mixx Sailor Moon comics were quite good (my books still are in great condition after 15 years and the art doesn't look photo copied,) they're not enjoyable to read. Kodansha didn't do anything to "Westernize" the manga, except translate the actual words. Whenever there is background noise spelled out, it's still in Japanese. You read the story from right to left, like the Japanese books. The names were not changed. The story was not altered to be more "kid-friendly." This is Sailor Moon left untouched, except for the words that were translated.
Any fan of the series, even if they haven't read or watched it for years, will love Kodansha's translation!