My wife and I bought both of those exact tents for a side by side comparison. Uliltimately decided on the Nemo after having them set up right next to each other.
It definitely felt sturdier, higher build quality. It was an inch or so taller, felt bigger and had bigger vestibules. Side by side it felt much bigger overall.
If weight was primary concern, copper spur was lighter by a couple of ounces.
Both are good tents.