Depends on where u gonna use it. Though both are useful in pk as well as pve. Well I got 2 barbs(sage&demon both) and preferably go for sage when I attend Mass. To tank and cc.
Demon efficient in mass as well ,so u can chi up ur squad and yes also u have the advantage to drain down ur targets chi. Bt with demon u need like way good def stats or like a slave healer on u .(just kidding). Well stats doesn't matter much to me ,if u know how to sustain urself u can.
So for the time being go with demon coz will help u with both pk and pve.