I've been using OrientDB for the last 7 months and as such I've been following @lvca and @phpnode (OrientDB node.js driver creator/maintainer) work closely. I have great respect and admiration for both and for what they've achieved!
@lvca, I find your comment distasteful and it's not the first time I see you trying to shutdown people who criticise OrientDB (https://news.ycombinator.com/item?id=9253488) when you should really be thanking them for exposing the issues they face (a lot of people don't go public). It would be more productive to engage @phpnode, @anonwarnings and others, listen to them, raise issues in the bug tracker and address them. Accusing people of trolling or flaming doesn't benefit OrientDB or its users at all...
Unfortunately I haven't tried ArangoDB so I can't make any comparisons with OrientDB but I hope both succeed!