My typical use for QCad is to draw two or three views of "all" parts in what is often an electrical enclosure of some type. Parts range in size from 0.1" to 10" (maybe a few feet in extreme cases). I generally make a layer for each view of each component; any parts that I make myself will get one or two dimension layers.
I recently upgraded to 2.1 and found that some views of some parts end up with empty printer output. So far, it has always been small parts that have failed to print. I have had one example that began to print again, perhaps because I increased line thickness.