I typically do use a groundcloth. The floor of any tent usually takes the most abuse, so I prefer to to protect my investment: not only to prevent holes in the tent floor, but also from objects that might damage gear inside the tent (mainly inflatable sleeping pads). For my car camping tent, it's a big generic tarp. For backpacking, I have one manufacturers footprint for one of my tents, and a piece of tyvek for the other. I prefer to accept the few extra ounces & hassle for some modest protection of my gear.