Wow, and just three or so months ago plenty of people were saying that Pokemon Collector is a staple and that you HAVE to run 3-4 of them in every deck :/ . Personally, I use both because my deck is relatively abundant in basic Pokemon. I still prefer Collector though, since its reliable, and you got a full 3 instead of 2 (maybe, if you get heads enough!) from Dual Ball.
I can see what the other side is arguing though: Much much much more frequently, it would be better to use a Draw supporter, and you can use Junk Arm to get some more basics, or have a second chance if you whiff on the coins. I personally think keeping at least 2 Collector in the deck is a great idea.