That's a complicated question.
I would say the negative and the positive balance each other out, but then of course I am not languishing in some unknown torture camp somewhere. I may have a 'rich white kid' perspective on this, but I wouldn't say it matters what people are fighting about. if there was no religion here tomorrow, we would fight over different thing.
There would also be fewer conflicts if there were no elections, or if every single industry was run by a monopoly, or if there was only one gender. Heck, there'd be a lot less conflict without humans. Apparent absence of conflict is a negatively defined (and therefore unhelpful) criteria for "the good," don't you think?
Conflict is intrinsic to the human condition, with or without religions for people to hijack.
You could argue that religon is simply a way to justify various actions. You could say that the Crusades were simply to take more land and Christianity was only justifying that by saying God ordered it thus. Now that does make me a blasphemer and im sorry if that offends anyone. But really If god wanted Jerusalem in Christian hands from the Crusades.... why didn't they hold it? And honestly With the massive similarities in almost all religons we could all believe the same thing just different ways. A christian's god may equal to a muslim's allah. Would God/Allah take the holy land... from himself? And for the record im hindu and absolutly unbiased. Just using that as an example.
Soooooooooooooooooooo Basically it really depends on whose hands it is in. Its a weapon and works completely for whoever weilds it. Also we've all been saying that it can be both and it depends for 41 pages now. Can we all just agree thats it?