I guess I am lucky, but I haven't had problems through all the Macs I have bought. It may be because I haven't bought rev A of any product.
The eMac was 2nd gen. No problems.
The iBook was 2nd to last gen. No problems.
And the Intel Mac mini is just an internals change. We'll wait and see.
If my Intel mini conks out unexpectedly, I will give Apple one more chance, because they haven't worked with Intel hardware extensively like PPC hardware.
At the same time, there is a price to pay for lower prices. Would you be willing to pay premiums for quality? I'm glad Apples are cheaper, but not glad about the downturn in quality. I think I would pay a bit more for quality, myself.