Fiio E7 + E9 vs Nuforce Icon HDP vs something else?

I'm looking for whatever will give me tonnes of power (to drive even hard to drive current hungry hp's easily like K701 and voltage heavy hp's like some 600ohm models). Would the Fio E7 + E9 combo be better for this or the all-in-one Nuforce Icon HDP? I've read good reviews of the Nuforce esp. with re. to synergy with the K701 - but is it powerful enough to handle any headphone you throw at it? Which of the two options is better value and better quality outright?

Also, would another option entirely give better sonics for the buck in this sort of price range such as a Cambridge Audio DACmagic + Schiit Asgard?

EDIT: oh yeah, I should also mention that I'm also looking for something that will really bring out the bass response of the HD650 and have a strong and deep (sub bass) performance generally.

Thanks in advance!!