Personal preference I guess. TO me, Drudkh doesn't offer anything I can't get from Burzum or Bergtatt. So I don't find them to be too special. That's not to say I don't enjoy the two albums, but I get very bored of them, very quickly.
If you'd of asked me this when I first discovered these two bands, I would've said Drudkh is the better band, but HF continues to impress me over time while Drudkh has fallen to the wayside. Drudkh is more immediate, easy listening, while HF requires patience, at least for me. And like some others around here, I think Drudkh is way overhyped for what they offer. I like their albums, but they are far from classics.
ANd to be honest, I find those weird Ukrainian folk songs to be somewhat annoying on Battlefields. I'd much prefer ambient pieces. But the music is divine in a sinister sort of way, kind of a more horror-type Graveland. Bad description, I know.
Battlefields is HF's best album in my opinion, so take that as you will.