I can only truly recommend this game if you've played the original.
There's controversy that this could have easily been released as DLC, but I'm not reviewing the politics of game admissions.
With the Director's Cut of this game comes a brand new narrative as well as a new soundtrack. They are both welcome additions to the game, alongside reworked puzzles, new secrets, and the previously released DLC. There's not a lot of extra things to see or do, but for a returning player who wants a bit more of the Q.U.B.E. universe, $5 isn't a big hole in the pocket.
However, the reason I prefer the original over this version is based on two things; the first being the actual lack of story in the original. There was almost a haunting mysteriousness to it, in the sense that you never truly understand the game as a whole. You pick up bits and pieces of things, formulating and speculating the who and what and where and when, but in the end, there were no concrete answers. These are the elements that made the game enjoyable for me beyond the gameplay. It was the time I spent wondering, "what really is behind all of this?"
The second reason being the soundtrack. The original game has a much more upbeat, ambient electronic score. It's catchy, it's fun to listen to, and I found myself listening to it even outside of the game. While the new soundtrack isn't necessarily bad, as it has been tweaked to fit the new found atmosphere that coincides with the added narrative, it simply just isn't as memorable. There were a few tracks that I did enjoy, but in the end it cannot compare to what was.
If you haven't played Q.U.B.E. do yourself a favor and track down a copy of the original. It's a short, simple, but entertaining and involving. If you're a returning fan who doesn't mind throwing a fiver down to replay and re-experience the game in a different light, go for it. It's not the best five bucks you'll ever spend, but I personally don't have any regrets. It gave me an excuse to have some fun with it again, and most importantly enjoy myself. After all, isn't that the point?