Balanced, the top one. HM901 is superb, and I agree, MA9 with standard card may not be better (actually is different and hard to compare).
But I got golden amp for 400 bucks loaded with quad opa627 and quad of opa827 as buffer and it has much better dynamics than HM901, not to mention how realistic sound is (I did blind tests with my wife too, what she said:
"wow, this is really good one, you can immediately tell its pro" (ma9 tested)). Its quite cool, ma9 cards are easy to mod, currently im burning opa211 newest chips for ma9 balanced amp (from ad797 amp), it sounds even better than hm901 too (actually hard to compare its very dark chip and very very entertaining).
On other hand, the ibasso has much better bass then hm901 (it sounds more realistic and better kick). Such a no fatigue power, zero distortion - that cute digital signature. You feel like "darn, this is expensive sound"
))
HM901 is impressive too but you will have headaches from "in head" sound type (its just reality), not to mention that darn software.... yuk!