I have both and really like both. To me they aren't comparable and both have their place. On a tree I'll take the millennium tree seat all day long but it may not work with all set ups like the one shown. It does just strap around the tree and I wouldn't want to strap it to the ladder. With all that said; I agree you can sit about anywhere on anything with that fat boy cushion and be comfortable and somtimes a rock may be what's available. Also as stated its good in a shooting house and the tree seat is of no use. There may not be a tree around. The reason I like the tree seat better is because it has great back support as well as being comfortable to sit in.