As mentioned in another thread, I'm trained in 4 styles, but, I am no expert in all of them. I like to be a well rounded fighter (especially stand up) and I'm trying my best to do it all. I like to exploit my strength and use it to my advantage.
In my opinion, its good to mix it up and learn as much as you can. That way, you know a little bit about everything so you don't get caught off guard. But with all the available styles, its difficult just in case you pass by something/someone that is unorthodox.