Hi Thunder9,
> almost sure it would be a PC not Mac
You will find more tools and support on the PC side of the force.
The PC & other hardware is cheaper too, of course, it's your money: buy the hardware that you want to use.
>but if I did choose a Mac I'd have a lot of work ahead, I'd have to re download all my CDLC's
"Yes"
it is not impossible to convert files to apple format, but it might take some time.
Link to the guide here:
http://customsforge.com/topic/33889-how-to-add-custom-songs-on-mac/
>and purchased songs, right ?
Yes.
I Googled for the DLC compatibility, but i got some mixed results. I suggest that first you make sure that you can use your PC DLC with apple first, so you don't have to buy the same music twice.
>When i log in and download the game if I chose Mac would steam where i purchased RS and RS 2014, download the correct version or would I have to buy the Mac version?
Good question, i have never installed the apple version, so i can't advice you with this. You should check this too, with the steam support.