Both are important, but as a beginner and if I where forced to choose, I would choose the technical ability.
When people start from scratch, a MA is seen like any other service... I pay -> I want to learn nice stuff, quick, and in a good way.
If the sensei is a dumbass in his real life, it's secondary (for a certain period of time...) if he can teach me well.
You will find many examples in many sports/activities: a lot of champions/artists are dumbasses in real life... they simply put their natural talent to work, and students may surely benefit from that talent.
The human aspect emerges later: I'm practicing from only 10 months, but still I've seen many people come and go after few lessons, all for non-sensei related reasons, well before they can establish any kind of "human" relationship with the dojo... the vast majority leaved because they had a completely different idea of Aikido (Seagal films anyone?) and came to the dojo almost completely unaware of what Aikido or a MA is (I bet this happens in all MAs dojos, too).
It's probably a matter of what you're expecting from entering the MA path.... and it's probably better to grow fast technically and then switch to a nice sensei, than agonizing with a nice sensei struggling for years to reach a decent aikido level, and then fill the technical gap when you switch
I choosed my sensei after 3 different dojos free lessons for a third reason : he's able to explain WHAT, WHEN, WHEN NOT, WHY and FROM WHERE of every tecnique in an extremely intuitive, practical and didactical way, even if he's not the best (ranking speaking) on the market.
In a word: didactical, which I think it's different both from human and from technical qualities, and a factor worth mentioning in the poll