If you can build it in the right spot quietly, natural ground blinds are great. For spots where you can't or you need portability, the pre-fabs are great.
No reason not to have both at your disposal
I had three hunts this year in blinds, one from a natural blind and 2 from a pop up. Had shots each hunt. I was worried how the deer would react to the pop up, as I didn't brush it in, but they could care less. At one time I had 4 does within 3 yards for 20 minutes. No deer gave the blind more than a passing glance then completely ignored it.