The ones we use are 4x4 posts (up to roof), 2x6 for floors, 2x4 railing, plywood sides, corrugated metal or plastic sheets for roof (on angle). IMHO, the more cover you can give it, the better. They are a better option for rifle hunting than shotgun and BP, unless you're putting out a little enticement. LOL... and, that likely depends on your situation - my son killed 4 deer on Sat. at 73-105 yds. out of boxes.
As for comfort, it's tough to beat hay bales if you don't need the elevation.