[TrickyRick]

Yes, however most computers are marketed using GHz numbers, not experienced performance (And in the cases where they are it's relative, like x times faster than before). It's hard to show a 17% slowdown to a store clerk.

Don't get me wrong, I'm all for being able to return a product that's 17% slower today than yesterday, I'm just saying it might be difficult since it's an issue that requires a degree of technical knowledge to understand which most store clerks don't have.

[maksimum]

I agree with most of what you say, but why do you take for granted that it's up to the customer to demonstrate that the product is defective? Furthermore, where does the idea that the customer must be able to communicate this to a uninformed clerk come from?