Brenton's edition is riddled from start to finish with extraordinary errors; and beyond this, is not truly the Septuagint: it is essentially a Greek version of the Hebrew canon, so reassembled and manufactured by Brenton from LXX texts. It includes the books and verses of the Hebrew canon, with non-Hebrew material as an apocrypha, and the in-line content of most books altered to accord with the Hebrew editions.
While I was aware that Brenton's translation left much to be desired, I was not aware that the Greek text found in his edition was so far removed from the original LXX.
As such, I'm left needing to buy another Greek Old Testament. The only available adition I've come across online is Rahlfs and Hanhart's Septuaginta. The edition is based on the Codex Vaticanus, but with the Codex Alexandrinus and Sinaiticus being prefered in certain places.
Is this a good edition to get? How much does it differ from the texts used in the Church's liturgical cycle?
Also, if I go to a normal church bookstore (or the one at Essex), will all the Greek Old Testaments correspond with that of the Church, or are there varied editions? And if there are variations, which should I get?