To throw my 2 cents into this:

What FPS games do you play?

The most dominant shooter games for PC are Team Fortress 2, Counter Strike, and Battlefield. If you play COD or Destiny on your PS4, consider whether or not you'll fall in love with these three games on PC.

It doesn't matter if keyboard and mouse are exponentially better for shooters than controllers are if you don't like any of PC's main shooters. This is coming from a Halo and COD (for consoles) player who can't get into those three games.

There are, of course, other shooters on PC that you might fall in love with, but almost all of them suffer from low population, which is another thing to consider.

PC is superior and PC gaming is superior, but superiority isn't always the best way to make a decision. Look at what games PC has to offer and do a fair amount of research, maybe even find a way to play Team Fortress 2, Counter Strike, and BF4 on a friend's PC?

This isn't always an easy decision. Don't be persuaded by PC's superiority. Look at its games and whether or not you want to play enough of them to justify building/buying a strong PC. If money's not an issue, I say keep your PS4 and build a PC. Won't hurt to have both.

And just to play devil's advocate, I've never had a problem playing FPS's on consoles. I think the biggest difference you'll come across is the general play-style and maturity of the communities.

People get caught up in the superiority of PC. Don't allow that to be your deciding factor to switch over. How much fun will you have on PC? Will you deem switching over to PC worth it? Will you fall in love with what PC has to offer or will you miss your PS4? What good is using kb/m over controller if you miss using the controller?

Good luck in your decision.