So I've spent several hours with the PS4 Slim, and here's my experience:
- The fans are super quiet, I played about two hours of Bloodborne and I couldn't hear them at all even if I muted the TV. On my launch system this game made the fans work loudly.
- The disk drive is still kinda loud, but most games don't read constantly from the disk so you're not going to hear it often.
- It doesn't put off as much heat as the launch PS4. My original PS4 used to heat up my apartment on its own, the Slim still puts off some heat but nothing like the OG console.
- The design is really sleak. Some people miss the light bar, but you wont notice it once it's gone. Plus getting rid of the glossy finish of the HD face plate is especially nice.
Honestly if you own a launch system that's loud af and wanna replace it, I'd say take advantage of Gamestop/EB games trade in program right now. Some might say you shuold wait for the Pro, but if you don't care about 4K there isn't much reason to wait.
Good investment, I'm quite happy with it.