I have actually been wondering about the quality of those gboxes. I ended up getting a 2x4x4 lighthouse hydro and I am honestly really surprised with the quality. I had heard very mixed things. Some people have said they off gas badly enough to kill plants so I will be letting it air out.
Edit to suggest tent.
http://www.amazon.com/Indoor-Grow-Tent-Protected-Waterproof/dp/B003ATF4WC
I used the gl40 for a couple very small grows with a Mars II 400 and I can say it was pretty decent quality. It did have plastic connectors though if that is an issue to you. I would definitely go with the tallest tent you can fit in the space, you will thank yourself. I have been limited to 4 feet and it is a challenge I can tell you.