Plain and simple: talk about the systems that you have trained in.
I trained for about two years straight as a teenager in Shorin-Ryu, an Okinawan karate style. It gave me a strong foundation for my stand up game, but zero skills in ground fighting / grappling. To be more versatile I've been training here and there in jiu jitsu / wrestling with one of my friends that went to MCMAP instructor school.
For me, I started with Karate as a kid...then used it (perfectly I might add) when I was getting jumped by some bullies. If it would have been a tournament, I would have won but instead got my ass kicked. I then found a real MMA school...not for sport. We had more than a dozen instructors teaching Muay Thai, Silat, Jeet Kun Do, boxing, arnis, Savat, Greco Roman Wrestling, Kenpo, and Jujitsu. My next encounter with the bullies was a few years later when I was in ninth grade...I was arrested for almost killing one of them and assaulting a teacher that tried to pull me away. I have been teaching real MMA ever since. In my opinion, there is no one best art. Though there are arts that are better for particular body types such as short and stocky or talk and skinny. One should look at the history of the art, the people who created it and why, than analyze what they are looking to get out of it before they decide. The best thing I’ve ever seen was duplicating the school I grew up in. Six amateurs were all paying for martial arts classes at different schools. We would meet every Thursday and share ideas then spar.
Radical, man!
I definitely agree that there is no one best art form. Diversity is the best tool that a warrior can have in their pocket! It's super insightful that you mention certain body types are better suited to certain styles - I don't think I've ever heard anyone say that, and it's so true.
I have mixed feelings about having never used my hand-to-hand skills outside a training environment. It's strange to say that I've been in a few gun fights but not a fist fight. That's how life goes, sometimes!