I ended up water cooling one of my PS4's and posted a video of it incase anyone is interested in checking it out. Im going to be running some heavy games in the next week or so and want to see what differences I will get in temps with water cooling.
Well with water cooling you generally get significantly lower temps than the air cooling, and with lower temps you have better performance, no lags when they system has been running for long periods and still with the standard air cooling on the ps4 people still complain about having overheating issues. I dont know if you have felt the heat blowing out from behind the system but eventhough its from the PSU as well, the processor generates a good deal if heat. So my answer I guess is why not? I had some spare time and wanted a new project so I decided to water cool it.
I notice you said "one" of your ps4. So I assume that you just wanted to do something cool and make something unique. And just happen to have the bank to back it up.
Looks huge but neat.
From my perspective...
Completely and utterly useless waste of gaming funds and resources.
Over 8 hours of ACIV, Resogun, War Thunder and a few other 'lighter' games, the air coming out of my PS4 is only 13 degrees (F) warmer than the rest of the room. Room is 68 degrees, air coming off the PS4 is 81 degrees. That tells me the internal temp of the PS4 is likely in the low-to-mid 90s, which is optimal for an AMD chipset.
By comparison, my MacBook Air (intel i5 chipset) blows air at about 130 degrees after only an hour or so of Portal 2.