When I started BJJ, I thought that it could never be useful for self defense, but now I come to realize how useful it is.
Anyway, back to your main question. We aren't here to tell you which martial art is better, so it's all about your opinion. Both are extremely useful for self defense. If you have doubts about BJJ's effectiveness, find a school that specifically teaches self defense BJJ and take a tour (eg. any Gracie JJ school). Remember, BJJ was invented FOR THE PURPOSE of self defense. It wasn't until more recently that BJJ as a sport became popular. I suggest you decide whether you want to focus on primarily groundwork or primarily throwing. Look into each one a little more before you make any decisions. When I started BJJ, I thought that it could never be useful for self defense, but now I come to realize how useful it is. There are pros and cons to both. Here are some: