Able to speak only for the DirecTV protection, at least as it's offered to us here in OH. It covers the cost of any service call and any necessary repairs that might need to be done to any failed equipment. I doubt it covers any problems with your home's internal sat cabling, electrical wiring issues, surge protectors, and things like that - items that aren't from DirecTV.
Last I checked, a DirecTV service call alone was $49.
I view this type of 'service plan' like any other form of insurance: A complete waste of money..............until you need it. Then you're glad you have it. On the other hand, if you don't opt for the service plan and go for years without any problems, you're probably money ahead even when a problem does crop up.
Pick your poison!!
It becomes a personal preference.
Bill