I tried the Valkyrja cables a month ago. I thought they were quite good. I have Quattro Fils in the system now, and I also have the Shunyata Aries interconnects. The Valkyrja is clearly more transparent, especially from the upper midrange up.
Interestingly enough, Jonathan Valim made a comment in the most recent TAS, while comparing another interconnect to the Valhallas, that the Valhallas were gently tipped up at the top and light in the bass regions...
I hear it as more "light" on the soundstage as in, say, a 50 watt bulb in contrast to a 100 watt bulb. That was the most noticeable difference between it and the Quattro Fils. But that open upper midrange is gorgeous! Wow. I see how important it is to have that if one is to experience a true sense of "openness" in the musical presentation.
As for TAS not writing negative reviews, I have to disagree quite strongly. Reading this thread, I'd think you all are recent readers of the magazine, 'cause us 'old timers' (20 years or more of reading) saw PLENTY of not so good reviews. I think what you might be seeing is newer reviewers who have a bit less experience with live music or are less observant than the "star" [read: older} reviewers, hence the reviews seem less critical of the component under review - and that's quite a bit different than suggesting that the mags all give good reviews. They don't. That's why HP hasn't written about SACD much: he didn't like it and didn't want to give thumbs down to component after component.
Back to the Valkyrja: it's a great interconnect, regardless of what else out there might be "better."