Judo is awesome, but competition butchered the art. BJJ is hipster Judo, ingrains bad habits, but has the most developed ground game of any sub grappling style. It's never good to go to your back purposefully. In a live combat situation, the last place you want to be is on the ground. You will get the shjt kicked out of you. I think catch wrestling is where it's at. They start standing, they work takedowns more than most other arts, they incorporate throws, they don't lie about the importance of strength, they have submissions, and there's not many banned techniques. Grappling alone isn't enough though. I think western boxing and kickboxing are more important. Style isn't everything either though, rules just shape the environment, gear people towards certain things. The less rules, the more realistic, but also, the more dangerous. Finding a good school is the most important thing.
I've trained Jiu Jitsu for almost 10 years and I think it's a cult of elitism and egos, that their philosophy is dishonest, and I recognize the bad habits that it's ingrained in me. It has some very valuable moves, but I'm not a fan of the art in general. Jiu Jitsieros go to their backs like nothing and struggle to take even high school wrestlers down, without wrestling and/or judo supplementation. Catch wrestling is by no means perfect, but it's more complete. What they don't have is sweeps, which I think is Jiu Jitsu's only saving grace.