I was the other way round.
I got into LR during my days when using MS Windows.
When i moved to Mac, and Apple launched its Apple Store with Apaerture going for a mere $40, i thought i'd give it a go. It sits in my wife's MacBook - but i couldn't get used to it.
So, Lr3, and Lr4, when it's released, will continue to be my main tool of processing and managing pictures.