Recommended USB- SPDIF converter for Metrum Octave

I am looking for a USB to SPDIF converter to use with a Metrum Octave DAC. The primary ones under consideration are:

1. JKSPDIF Mk III ($460)
2. Audiophilleo 2 with Pure Power ($999)
5. Wavelength Audio WaveLink ($900)

These configuration would be computer->USB to SPDIF->Metrum Octave->Rogue Cronus->Harbeth P3ESR

Aside from the obvious cost consideration favoring the JKSPDIF Mk III and Linux support favoring the Audiophilleo, can anyone comment on how the sound compares for any of the units?

I would prefer to hear from Metrum owners and owners of the aforementioned converters, but any other recommendations from owners of similar USB to SPDIF converters using them with the Metrum Octave would be appreciated. The reason for asking before looking further is that I came across these comments from John Darko on the DAR website.

"How does the Audiophilleo compare to the JKSPDIF? I get asked this question a lot. I've tried them both with a wide array of budget DACs over many, many months. There really isn't that much to separate them sonically. I could happily live with either (in the long-term) but I distinctly preferred the JKSPDIF with the Metrum Octave - it seemed to bring out more elasticity and tame some of the glassiness."

"Last week a buddy and I sat down to compare four different DACs. Whilst I won't divulge the conclusions here (this piece is about transports, remember?), we both agreed that the Audiophilleo seemed to overcook the upper-mids on a couple of decoding boxes. This wrinkle was ironed flat with a digital attenuator. The JKSPDIF MK3 seems to be kinder/gentler overall. Perhaps it's the battery technology?"

Can anyway comment as to whether or not they have shared his experience of the Audiophilleo? I believe his experience was without the Pure Power unit, and I was wondering how much of a change that had brought to the table for Audiophilleo owners, understanding that these characterizations are often system dependent.