This is, of course, a question that can never truly be answered in an objective way. My own view is that good is a stronger force than evil today, but that may simply be because I live a good life in a free and prosperous country.
I would argue that good is a stronger power than evil today because most people live lives that are fairly happy. Compared to other times in world history, we are much less likely to be killed by rampaging armies. We are very unlikely to be enslaved. In most countries of the world, we are unlikely to be persecuted for our religious or political views.
To be sure, there are conspicuous examples of evil in the world, such as the people who commit mass murders or terrorist acts. However, it seems to me that such people are cancelled out by the people who do acts of goodness and kindness to one another each day. The good that the majority of people do is rarely as splashy and conspicuous as the bad that a few people do. But I would argue that it is, overall, more important.