Ugh! It happened again - I crafted an long, detailed response about my studio set up and my real-world example, but when I hit submit it got lost in the ether...
Oh well, here's the shorter version - I have my entire synth studio being fed from a single outlet. No noise, no anomalies, no weirdness that might be power related that I can tell. I have a Furman M-8Dx plugged into the wall and four PST-8 power strips into that. Everything except the computer and its two monitors is either in a PST-8 or direct to the M-8Dx. That includes seven hardware synths, two 7U cases full, two Yamaha HS80Ms and matching subwoofer, Presonus StudioLive32 and a ton of other stuff like lighting and pedals etc. I keep the computer on its own power strip plugged into the wall so I can leave it on and have a single switch to power off all the other gear. I added up all the power requirements for EVERYTHING in my studio on that circuit and it's about 12 amps (remarkably low for all that gear).
I "believe" this is a safe setup but I am not 100% confident. I'd love to get a UPS but they are expensive at this scale - like $1,500 for a Furman. Is it really necessary?
I am not an expert here either and would love to hear from other folks.