it depends on the length of the wrap. shorter ruck and longer DH. but i also prefer something thinner and slippier in a dh and thicker (relatively) and grippier in a ruck.
There are some great all-rounders, though, which I can do either with in a size 4. My karma is perfect for this, for eg.
DH is more comfortable, generally, though, again, it depends on the wrap. the dh is generally more supportive.