QS, Pennzoil, Havoline, and others have their own guarantees, there are obviously limitations with all of them. Some say you have to take your car to a shop that uses their oil, some say you can do the changes yourself. Interestingly I noticed that Pennzoil used to explicitly state that it's valid even if you change your own oil, however with the new website it doesn't directly say that any more (though it doesn't say anything to the contrary either). Obviously they all state you have to use their product and only their product, make regular changes within the interval they specify, etc.
What I find interesting is that the Valvoline website says you have to register your car before 75k miles. Most of the other ones require you to register your vehicle before 36-48k miles