I have used both. At my hunt camp that I sold I had a 6' x 6' little cabin built from 2"x2" and plywood with a tin roof and 360', 1' x 36" windows that could be opened individually. It was 8' up on 4"x4" pressure treated posts with appropriate cross members to stabilize and prevent tip overs. It worked well in it's location. Floor was completely carpeted with a swivel chair so one could move around in silence. I would suggest six foot square as a minimum size as it gives you room to move to take off a clothing etc. plus your chair without banging around making a racket.
At my new place I hunt from Ameristep Dog House tent style ground blinds. Cabelas had them on sale a few years back and I bought 3. I set them up in various locations I wish to hunt and leave them there all fall. I can do that without issue as I own a large acreage in a location that I don't get trespassers. I had a bear visit one last spring and he made a new door and window in one. All reparable. I put a Cabelas swivel hunting chair in each one which has worked very well in keeping the noise levels down when moving to just the right position for a shot.
I like the ground blinds as they are easily moved or repositioned, cheap compared to building a good raised wooden blind. The draw back is they can be easily damaged by weather, falling trees and branches or curious bears.
I stopped using actual tree stands of any type when I a good friend at my old camp had a tree stand part break, he fell 15 ft. , broke his back , and is now predominately confined to a wheel chair. When he was in the rehab hospital he introduced me to two other fellas that were learning how to cope with paralysis from tree stand accidents. So I over built the 6x6 on a post frame. At present I am happy in the ground blinds, if the chair breaks I can only fall 18".