And why didn't you use AppleCare to get them repaired/replaced free?
It doesn't add that much to the cost and greatly improves overall service over the life of the machine. I have yet to pay for a single repair to any Apple computer I've owned. My current iMac is 4 years old; I have a MacBook 1st-gen Intel; an iBook 9-10 years old and a Mac Mini about 7 years old--all still functional and working as well as they did when new.
I won't deny that any brand can have some failures, but based on different opinion polls, Macs tend to fail less often than any other brand and the service when getting them repaired is significantly better in most cases. Of course, your experience may be different.