i have both kinds. kegs are kegs to me. i use flared fittings for everything, so i just need the QDs (quick disconnects), and i'm good to go. it allows me to be flexible in the deals i find on craigslist usually.
in fact, chimone, if you don't mind shipping to Texas... i could take the keg off your hands. haha.
i think pin has some advantages over ball as well. the co2 side has two pins, while the liquid side has three. ball lack is a bit more ambiguous, and you can make a mistake easier with the ball lock. ball lock kegs are generally much more available and easier to find. some places sell the QDs cheaper for ball lock as well.
it is also a matter of size. pin lock are generally stumpier, meaning shorter and wider. for a mini fridge, this could be important as it could possibly fit just right and a ball lock would be too tall. it could also be in a chest freezer where ball lock can fit more but pin lock can't fit as many (this would have to be a fairly large chest freezer to see the difference though)
i personally use whatever i can find for a decent price. if that is ball lock, great, if it is pin lock, great.
just get flared connectors, don't get barbed. please don't get barbed. you will thank us when you realize you need to take off the hose for cleaning or swapping, or getting both kinds of kegs.
hope this helps!
