I would recomend listening to somethiFROM, MSB, dCS, or Chord before saying the AKM is the best. I still own an SP1000 with the AKM 4497eq chip but it is bested by my Bartok, MSB discrete or Chord TT2 and Dave.
AKM makes the best DACs
OK, before you flame a reply to my heading please read this section.
It is a terrible idea to judge a DAC based on the chip. I don't think consumer's should ever do that. I think there is a lot that goes into a good external DAC unit and the converter chip is just one of many factors that go into the final sound.
Having said that, it turns out I tend to like the sound of DACs with AKM chips over most others. A long time ago I would have said the same about Burr Brown.
For converters which use an all in one chip what is the brand you find yourfself more likely to like the sound of vs. not?