Behind is generally easier with just a side step and throw. Throwing in front requires extra movement and a change of direction.

I typically agree with Ken. However, if your catcher's learn both methods, they are able to execute whichever one is most effective for that play.

There may come a time when stepping forward is the better method in a particular circumstance and if the catcher knows either one, she can simply make the move the situation presents.

I agree with Stacie, you need to know how to do both because every situaton is not the same. Practice both better to be safe than sorry.