I ordered both the 2-shelf cube, and the 2-shelf rectangle units. I got the 2-shelf cube last night, and I have to say that I did not have any trouble with assembly. I am a paper crafter, so lining up edges with sticky adhesive where you get one shot at it is old hat for me. And the dowels lined the walls up great. Even though I was careful and deliberate, it still took less than 5 minutes, which was just AWESOME to me. One recommendation I did not see in other reviews: DO A DRY RUN ASSEMBLY FIRST, BEFORE EXPOSING ANY TAPE. This way, you will be able to see if there is anything in the little pre-drilled dowel holes that might keep the pieces from sitting flush. You will also be able to better see how to line up the back panel straight. Also, you really should put these together on a flat, hard surface, like a wood floor. As I did my dry run with the unit, I noticed that the back panel piece was too long. When flush with the bottom, about 1/8 to 1/4 inch would stick up from the top. No problem for me, I simply assembled flush with the bottom, then ran an exacto knife carefully along the top edge a couple times, using a self-healing cutting mat underneath. It's all pretty now :-) As I assembled each piece onto the next, I tried not to lower the piece into place until it was lined up. Then I slid it slowly onto the tape, and pressed and held it there--you need to press straight down into the tape, be very careful and don't wobble the piece. Once I had all the walls put together firmly, I actually very gently set the unit on its front, so I could better line up the back panel. Also, putting the back panel on like that enabled me to push the panel straight down onto the tape and hold it there firmly for a few seconds, to let it get a better grip. All in all the assembly was fast and easy. I bought these shelves because they perfectly fit the sizes of the places I will be using them. I am putting one on each side of my monitor on the top of my desk, then will find a board to go across the top, to have more space to organize my stuff. (I wish this company offered just straight flat boards--I could use one about 60" long above my units!) My shelf seems pretty sturdy so far, but it is sitting on top of my desk, at the back, against a wall...so it is not going to be leaned on or anything potentially troublesome like that. I can't see using these reliably in any situation other than having them supported like that. I would bet that if you were to hammer little brads through the back panel, into the sides and bottom, that might help. But this product should be improved by the manufacturer, not the end-user, especially for this price. Now, for the bad news: even with the dowels and careful, thoughtful, assembly, my shelf unit does not appear straight/square. My husband measured and found what appears to be slight warping on the top and bottom pieces, which just adds up by the time you get it assembled. I also think that not having any alignment guides for the back panel creates a situation where you can accidentally adhere the panel at a slant, which doesn't help. I've cut some cardboard strips from the packaging to set under one side, and that will do the trick for me. I paid like $80 for these two 2-shelf units, because they were the perfect size for my needs, but that is just way too much for furniture that is so hit and miss with assembling square. (Even if the company can do better with that problem, it's still not worth more than $20 for this 2-shelf cube.) And like others have mentioned, the woodgrain covering paper peels back easily. I saw it happening in a place that's now covered after assembly, and I had not touched it in that area, so it was coming off by itself. If that piece had folded over itself as I was assembling, it would have prevented the pieces from sitting flush. I do have to say that everything was packaged beautifully...maybe that's where all the cost is! Bottom line, these work for the modular space I wanted to create. If you find something else that can work for your space, I'd go for that.
