The results showed up two important facts. First, there is image degradation with repeated trips through the DV codec. This seems obvious for a lossy codec, but some others have thought otherwise. Second, all DV codecs do not produce the same results. Though the DV standard is precise about how DV data is to be decompressed, there is latitude in how DV video is compressed.
Second place depends on a judgement call.
The Adaptec DV codec has color smearing to the left, more with each generation, but though Apple DV codec has no color smear, it looks more out of focus. First, what you can see on a computer monitor is different from what an NTSC TV monitor can show. And by the time you consider what a VHS tape can show on your average TV set these codecs will all pretty much look the same. It is always good to stay as high quality as you can through out production. Second, there is no sensible reason to ever run 15-generations of DV compression in a real production.