If you want a Printed Edition for study, then I highly recommend the ABP+ or the Apostolic Bible Polygot.
http://www.apostolicbible.com/bookstore.htm
Van der Pool (the translator) now allows the free downloading in PDF format from his website. You can also find this module in E-Sword and available in some online bible tools.
Here is an old video of him talking about the bible.
https://www.youtube.com/watch?v=JtAyzbZXP0I
Also, you can read the short introduction below.... It a nice read. It sums up the issue very well.
http://www.apostolicbible.com/intro.pdf
To me, its a great resource. If for nothing else, one can begin to see how the NT Greek text lived in the OT. He gives an example in the introduction about 2 Corinthians 5:21. This example shows the value of understanding the Greek OT.
Just a warning when dealing with newer Greek English translations of the LXX. (Not an issue in the ABP that I'm aware of) There seems to be a push to smooth over the differences in the Hebrew texts by appealing to the "root fallacy" in translating the LXX to English. In other words, they choose to employ a Hebrew to English translation and claim the word choice is within the "Semantic range" of the Greek text.
The NETS is good as well. It does follow the
NRSV and I'm somewhat on the fence about them doing such. The NETS is probably... better known to those who study the LXX.
I give the slight edge to the ABP because Van der Pool has done extensive work to actually follow/study microfilm of some very important source texts. He just hasn't relied on someone complying a text from various manuscripts. Add the fact that he's tied to a modify Strong's number system for word cross referencing..... and it a wonderful tool for Bible study.
Its a difficult task to piece together all the pieces. I'd be lying if I said I had completely. I feel like "I'm on the little end of HUGE task". I've really wanted spend more time digging through the text themselves but its somewhat overwhelming.
I hope this helps.