Assuming you have the disc versions and the codes ready, go ahead and install on new Mac. You can have the game installed on more than one computer.
The Launcher will look the same on Mac as it did on PC, as far as I know.
If you had the graphics settings on very low on your old laptop then you can try moving the settings higher on your Macbook once you are ready to play.
If you have old games that you want to continue you might need to transfer the save files over. I've never done this PC to Mac with Sims 3 but I presume it works - maybe someone else will say if not, or just try it!
Have fun with your new toy