Time consuming to assemble, make sure you have another set of hands to assist when building.  They look nice when put together.  Lots of headroom in the bottom bunk... which does move them up... so beware if you have low ceilings :)
Four stars only because there were two welded in nuts (one on each of the two units I assembled) that were set in place crooked... unable to install the bolts until I oblonged the corresponding holes with a Dremel AND there are no diagonal braces.  With something this tall a couple of simple diagonal braces would go a long way to making the whole unit much stiffer (I'll be adding my own).
PRO TIP: use blue threadlocker on all the bolts to help eliminate the need to retighten and prevent loosening.