Inverter generators produce commercial-quality AC power. The Inverter generator power is often equal to what you have at home. The problem is they are very expensive, often are only 120 volts and are limited in power. There is also too much electronics and much more to go wrong with them.
Non-inverter type generators are not so perfect. Does it matter? Often not. Most equipment today can handle some electrical noise. They have better power supplies and filtering than in the past. Internal power supplies convert the AC power into lower cleaner voltages that electronics use. A notebook computer for example runs off of batteries that are always on charge so if the power is lost there is no damage. Home computers should always have UPS power supplies to save them in the case of a power failure.
You are more likely to have electrical damage due to a local lightning strike then damage from electrical noise produced by most generators.
Even if you are using an inverter generator that converts the DC to an almost perfect AC there is always a risk of an engine hick up or failure and damage from loss of power then any existing electrical noise.
If in doubt use a UPS power supply so even if your generator does fail you always have perfect clean power and the time to safely shut down equipment or restart your generator.
What you need to be concerned about is power failure more than anything. Computers that do not run on batteries, for example, may be doing some important writing to your hard drive and get corrupt if power is lost. Same with your PVR.
Do yourself a favor and invest in UPS power supplies for your TV, Computers and Sensitive Equipment. They are your only guarantee. No generator is 100% safe.