In my personal notion of code quality, being correct counts for a lot, and this programmer aced the tests, while apparently delivering more within the deadline that any of the multi-person teams.

While writing the previous paragraph, I wrote 'programmer' where I had previously put 'implementation', because I would guess that this study's outcome is better explained by human factors than language differences.

I share the attitudes you state in your last paragraph, but I would add that we should be skeptical of concepts of quality that seem plausible, but which lack empirical evidence for their effectiveness.