Yes, absolutely agreed. Apple makes potentially the greatest computers, but their potential is frequently let down by their implementation, assembly and component choices.
I think this hits the nail right on the head.
I also think it's important, when discussing quality control, to distinguish between actual "quality control" issues (defects) and just "quality" issues (general sources of dissatisfaction). For example, the grainy screen on many 15" C2D MBPs (like the one I have) has always been a source of dissatisfaction for me, giving me a perception of lower-than-expected quality---but it's not a quality
control issue per se. Rather, it's a bad
component choice on Apple's part. That doesn't mean I'm any less dissatisfied by the poor quality of the display or that I excuse Apple for its poor choice, just that I acknowledge it for what it is.
I think most quality-related complaints on this and any other forum are predominantly quality issues rather than quality
control issues.
Between myself and various family members combined, we've purchased 11 Macs in the last 12 months, nine of which are notebooks. If we were to restrict our estimate to the number of actual quality control issues encountered, the defect rate would be about 27%. On the other hand, if we include all other issues leading to dissatisfaction or a perception of lower-than-expected quality, the "failure" rate goes to about 64%.
Both numbers are probably unacceptably high (for the price)---and I, in particular among my family members, am way too anal about this stuff---but I think it's an important distinction.