On spike/surge protectors, they are good for small spikes made by stuff like motors turning on and off. None of them have the ability to deal with lots of energy. The ones you plug stuff into can handle some spikes, the whole house ones can handle more. How good your ground is for your house can also affect how well they work. The quality of your ground is both the "do you have a ground wire in your wiring" and "how many ground rods do you have."
The spike protectors are good stuff, and for a lot of common things that happen they help protect your electronics. Typically stuff they can deal with are motors turing on and off, lightning that hits the main power line at some point more than 1/4 of a mile from your house, and spikes from power coming and going (the small period of time when you are loosing power or getting it back).
Now the power supplies in electronics devices are odd. There are a wide variety of supplies in use. Some of the smaller power supplies (100W or less) can run on 100 to 250 volts, 50 to 60 Hz, and can take just about anything. These are the small rectangular units like you see for laptop chargers and the like. They take whatever comes in, make DC, and switch it down to the right output. They could care less about the input frequency.
Other supplies are more efficient by syncing up with the 60Hz line and turning on transistors (or MOSFETS or IG Transistors) at exactly the right time. They can kick out if the line frequency gets off by a couple Hz. Since the transistors have less voltage drop than diodes, the supply is more efficient. These devices also have circuitry to correct for harmonic distortion and can be more fussy about frequency because of those devices.
At higher power levels, the supplies can only take their rated input voltage- they don't have the wide range of the lower power devices. So for a TV that might be a 90 to 135 volts range. They can take a few cycles in the 140V range. Above that, your surge suppressor should kick in. Some of these use the synchronous rectification mentioned above, some don't. So there is not good way to tell by looking at something if it's fussy or not.
So you can see where a lower power device like a DVD player might tend to be more tolerant than a high power Plasma TV. Unfortunately, there is no good general answer to the OPs question. In general, the modern switching power supplies that are indeed in everything are much more tolerant of over-voltage and off frequency input that produces of 20 years ago and many do well with generators.
But at the end of the day, you just have to try it and see.
Finally, a comment on UPS systems. In a very general sense, there are two flavors of UPS systems. The more common and cheaper ones sit there with the output of the UPS connected to the line. If the voltage goes too high or too low, or if the frequency goes off by more than a Hz or so, a big relay kicks in and connects the output to the UPS's inverter than runs off of the batteries. So your computer or TV gets to see a little dirty power, then loose power for a half cycle, then get new power at some different phase which may or may not make your device happy. But once switched over, you or protected from spikes and sags and frequency and no power at all.
The more expensive ones take the AC in, make DC which goes to batteries, and then always makes a clean sine wave AC that goes to the output. There is no switching on or off, and the output is always clean, spike free, and right on frequency. If you look at the output of the UPS, you have no idea if the AC going in is connected to the batteries or not. If there is input power, they lock and track the frequency so clocks stay accurate. If there is no power, they run the output a 60 Hz which is more than accurate enough given that the batteries only power things for so long. I have one of these in the house, and every computer and TV connects to it. I added special outlets when I built the place so I could have a single big UPS in the basement.
I know this is a wordy reply, clear as mud, and it solves nothing :confused2: but hope the information is useful.
Pete
