the other issue you also need to bear in mind is the MacOS itself as if you are an experienced Windoze user, does take some getting used to and isn't the big thing that many Mac users claim - I have a Mac at home and run Windows on other machines but experience still leads me back to MS for the trickier stuff as I know my way around that OS
tbh - you might be better off investing a more professional presentation package for your current PC - not an area I'm that familiar with though so can't suggest anything bar a professional graphics package that may do the trick