Thanks for your help guys! I've decided to go the UPS route. Does anyone know if stepped sinewave works with the new iMacs? I'd like to try the SurgeX but not sure if it works with new iMacs.
Let's undo some popular myths.
First, if a power loss occurs during a disk write or before a file save, then a drive simply reverts to a previously saved version. No data corruption. That corruption threat was eliminated by file systems developed before 1990. Unfortunately, a myth of data corruption lives on.
Second, get some numbers for a typical stepped sinewave (also called a pure sinewave) UPS. For example, this 120 volt UPS outputs 200 volt square waves with a spike of up to 270 volts. Is that destructive? Of course not. Because all electronics (including a Mac) contain superior protection. Protection that makes spikes from any UPS irrelevant.
Third, does power restoration created a surge? Only when myths exist. What is AC electricity? Power goes off and on 120 times every second. If power restoration creates a surge, then so does normal power that goes positive, zero, then negative, and then zero again so many times every second.
Fourth, two completely different devices are both called surge protectors. An adjacent one claims to protect from what is already made irrelevant by every Mac. Same internal protection also makes irrelevant 'dirty' electricity from a UPS.
Fifth, your concern is a completely different and rare transient that may occur once every seven years. An anomaly that can overwhelm internal Mac protection. And is only averted by the other completely different device with a same name.
That other surge protector must be installed where wires enter a building. Connected as short as possible to earth ground. Spec numbers that say it will earth direct lightning strikes and remain functional. And is a least expensive solution. This 'whole house' protector is provided by companies with superior reputations. Including Siemens, Square D, Ditek, General Electric, Syscom, ABB, Leviton, Intermatic, and Cutler Hammer - to name but a few.
Surge protection or 'temporary and dirty' power from a UPS are different solutions to different anomalies.