I've compared and listened to the trio plus, fugue, symphony, valkyre and pathfinder in a few different systems over the last few years. I previously thought the symphonies offered the greatest "value" in there line up- maybe they do- but not long ago I realized that value is not the right way of explaining it. I've also said in the past that as you move up the line you get more, that's kind of ambiguous and in a way inaccurate. Having personally owned symphony and pathfinder interconnects I feel I have a great understanding of just how much better they get as you move up.
When I purchased the pathfinders I was not anticipating on liking them much, I didn't think they were going to be much better then my symphonies. As soon as I put them in the improvement was dramatic, the biggest change was the air and three dimensionality of instruments, vocals or any other presence on the recording. Everything had gained its own "space" on the soundstage unlike anything I have ever experienced in my room before. A flute sounded light and delicate but true to what a flute sounded in the space a flute belonged. Dynamics increased signicantly which probably added to the air, space and all of the other new found improvements. Soundstage gained not only width and depth but accuracy(this is how you can, in a half assed way, say that it is "more" of the house sound), the back ground became a little blacker with greater contrast, speed and attack also became much better. So now the question is how can you compare a cable that is $1100 to one that is $6000? It hardly seems fair, but if your bank account will permit it and you want the next level, the improvements are there and well worth the price of admission- to this listener any way.
As to symphony vs. valkyre, I've only compared them directly once and in a system I was not too familiar with at the time. It was hard to draw a conclusion, the changes were clearly not night and day, but subtle. From my experiences as an audiophile these subtle changes are why we are in the hobby. When your listening to a piece of music that you've enjoyed 100 times in the past, and this time your a dozen little steps closer to connecting with the music- the money spent means very little. These subtle changes are also the things that make a system enjoyable day in and day out, reducing listener fatigue, allowing you to enjoy more music more of the time. Instead of throwing a lot of meaningless adjectives around, I thought, for a change, I would try to rationalize it as I saw it.