Sturdy for my teenage grandsons and looks great! Instructions were clear, but one piece was marked incorrectly and the packet was missing two wooden dowels (which we simply picked up at the hardware store).
The dark pine looks nicer than I expected at this price, but it is soft wood. 
Because of the high weight capacity indication, I wish it came with 10 instead of 7 slats for each bed. (Which is why I gave it 4/5 stars).
We put a regular twin mattress on the bottom, but put a bunk mattress on the top for safety, to not be higher than the rail.
Great value! Would buy it again.