Got to listen to it some more today...nothing has changed, I'm still impressed. What you want in a converter is not to be able to discern a sound signature. It should be entirely transparent and let the DAC shine...which is what the MK3 does. The MK1 was a bit soft and slow, the MK2 was somewhat dry and closed in comparison, the MK3 is none of that. It's fast, detailed, revealing, very open, noiseless/black, delicate and all this without a hint of harshness. Some of the greatest areas of improvement over the other transports are the tight bass and grain-free, smooth, detailed, extended treble. The best top-end I've heard in my system.
I can't find any flaws with the MK3. I can't give it any higher praise because up till now, that has happened with only a handful of the best equipment I've owned.
Just as a reference, I've owned the y2 DAC/converter, Musiland 02US (3 of them), MK1, MK2, MK3 and stock HiFace, both Asus Essence ST and STX, Teralink-X2 (twice) with linear regulated PSU + aftermarket silver USB cable. I've also used several integrated motherboard SPDIF outputs. The MK3 is hands down the best out of these, and they're all better than straight USB. If people are still using the USB input with their high-end DAC, they're really missing out on the potential of their source. The difference is profound.