Don't know how many have used it, but holy crap it's crazy easy to get everything I want.
I have Pokemon X. I started with Fennekin and Squirtle. Using JUST Eevees I was able to trade for all three x and y starters and all genereation 1 starters. I then used a Hounder and got Yveltal! And all these trades literally happened within minutes. I got Yveltal for Hounder in probably 2 minutes...why would someone give it away??
Just use it, its a blessing for 26 year olds like me who don't have any friends with 3DS's.