I enjoyed my time with the Diablo III: Reaper of Souls beta, but we still have over two months to go until its release. In an interesting turn of events, Blizzard may let users preload nearly all of the content at the end of this month, so when the actual launch hits, it'll just unlock. The reasoning towards this move is that when the game finally does come out it won't put a strain on their servers.
It makes perfect sense, and should help solve a lot of the connection problems that plagued the original launch. If you're still playing vanilla Diablo III, you should get all of the content updates as they come, along with the removal of the Auction House, which is coming up.