I can only comment from my perspective on the overclocking. In my case in order to get the maximum performance from the 5820K I needed to overclock. Otherwise it doesn't have a huge advantage over the older i7 chips. In my case it could be done safely within reason. If I had seen my cpu amps or temperatures rising to dangerous levels I wouldn't have done it. I wouldn't have tried it without doing my homework on it first . I would never recommend anyone attempt to overclock any system unless you know the hardware limitations.  I don't think that I will shorten the life of my system OC to around 4ghz since the design of the chip accounts for the clock speed set.
 
Overclocking is bigger with the video game crowd. The reason they do it is to get faster more responsive play on demanding video games. A few milliseconds can make the difference between winning and losing a game and we are talking competition here...nuff said.
 
In audio production it isn't nearly as important especially if you only record audio into your interface. I personally  did it because I could. No harm done. There is an advantage in audio work. 10% is a nice little speed boost :)
 
FYI- I got my Presonus talking again. Windows updates rolled back my audio settings.