THERE IS NO ANSWER WHICH IS BEST, friends. There is only your answer, but your answer is important
Here's my opinion as well. You see, I can tell you why I like a 6 string over a 4 string but "that's what I like." You can tell me why you like a 4 but "that's what you like." Are either one of us wrong? Are either one of us right?
In all honesty, I like the 6'ers because there are notes I can hit that I can't on a 4 string. However, as far as technique goes, I have a hard time doing things on a 6 that I can do easily on a 4, like slap and dig in. It's the difference between an F-350 Super Duty and a Corvette. They're both good for different reasons.