Well first Congrats on your new Mac!
Honestly its going to be a personal choice... I use iWork at home and for personal use, but I have to use Office for Mac at work. I personally believe iWork is easier to use and seems to be more reliable.
Next thing: Mail or Outlook?
Well I love Mail I would say Mail all the way. Super sleek look and really easy to use.
Now you are asking for an individual breakdown... so here it is:
Excel vs. Numbers: Excel
Pages vs. Word: Pages
Keynote vs. Powerpoint: Keynote
So I would suggest using iWork and Mail.
Wish you Best of luck!