That is a very diplomatic answer Even secretary general Guterrez would be proudFirst, both DACs are in my personal conversation for best DACs under 100k.
As for sonics, a good car analogy would be that the Tambaqui is like a Caymen GT4, while the Kassandra II is like a 911 Carrara 4.
The Tambaqui more about speed, detail and air, while the Kassandra focus is more on dynamics, power and analogue sensibilites. If the potential buyer is going to add a Aries Cerat preamplifier and amplifier, then the choice edges towards the Kassandra, (especially when using the high gain outputs of the Kassandra), as the Kassandra was originally designed to be a reference source for all the electronics and speakers that were developed subsequently.
These distinctions are subtle, as each DAC is still outstanding in the areas I mentioned where the other DAC shines. One really can't go wrong with either DAC. The choice comes down to personal preferences and system synergy.