The Bishops here in the U.S. have approved a motion to revise the Liturgy of the Hours, similar to how the translation of the Mass was revised recently:
ncregister.com/daily-news/us-bishops-approve-revision-of-the-liturgy-of-the-hours/ It don’t imagine it’ll be a huge change, and I assume laypeople will be free to use whatever version they’d like, and it will probably take several years to complete, but it’s another reason why it may be good to hold off on buying the 4-volume set for now. There’s nothing quite like shelling out a lot of money for nice books, only to have those books become somewhat obsolete several years later. It’ kind of like buying a computer…
That being said, I’d definitely recommend getting started with the Liturgy of the Hours, either with Shorter Christian Prayer, or with the longer 1-volume Christian Prayer. It would be really helpful to start praying it with others, to help you get a feel for how to do it (it can be a bit confusing at first).