There's not much love for DH right now, but I have to admit that I absolutely love this class and for me is stil no 1! I've also played CM Wiz and compared to DH it's just boring.
Hovewer building DH is most expensive right now if you compare it to WD and monk.
The expansion will bring some nice changes and buffs to DH's skills, so don't give up on this class. If you want to have some fun and a little bit of challenge and not necessarily want to kill mp10 in 2 days with DH, I say go for it