Ball locks are not better, just more common (in that more homebrewers use them).
If you want to take a keg to another brewer's house and hook it to their system, a pin lock probably won't work. Same thing if you take it to homebrew club event.
Pinlocks also have a larger diameter and that could effect how many you get in a kegerator. But they're also shorter so that could help in some cases. Also , often pinlocks don't have any pressure relief valves or they are set. It makes it a bit more difficult to purge the air out of a get.
I actually like the pinlock connectors better as they don't get gummed up with wort and can be easier to put on and take off the keg.