Nice and sturdy! It assembled easily, and it looks great. The casters on the trundle glide really well, too. The one thing is that the mattress on the trundle has to be less than 6 or it wont slide under, and most modern mattresses are thicker than that.
The mattress on the trundle slides around really easily, so the beds dont hold together to make a king well - you end up with a big gap in the middle that gets bigger through the night.