I think most people have pretty much given you an idea of where to go with this:
It ultimately come down to the games that you want to play. However, to get what is arguably the 'best' experience, both are potentially necessary.
Sony exclusives are definitely things to behold, and compared to Microsoft, they certainly have a comfortable and meaningful stable of titles that you will only ever get to play on PlayStation. There is also the ongoing support that we continue to see from Japanese companies with respect to support for PS4 (Ni-Oh comes to mind as a game that has stayed exclusive; the Yakuza series is another).
You can't beat the fact that Nintendo, however, has the 'most' exclusives, particularly with titles that, if you grew up with, have aged well and have shown new life on the console, showcasing rejuvenations of series that were thought to be stale.