About a year ago, I purchased a Shunyata Everest power "conditioner/distributor" and swapped my Nordost Valhalla power cables for Sigma power cables. Everything including mono amps got plugged into the Everest. The change was improved clarity, articulation, sound stage.. all the "cliches" really did improve.
I was so impressed, that I decided to try the interconnects.
I replaced all my Nordost Valhalla (latest version) interconnects with Shunyata Sigma (latest version). With each change, I noted a marked improvement in clarity, sound stage (width and especially depth), articulation, separation of instruments/voices, more definition in bass (and more bass per se). The Valhalla's were good, but always seemed to have a "veil" or haze obscuring some of the music. In comparison, the Shunyata's washed the dirty windows and brought all the light and clarity of image to view. There is certainly a synergy, that is while changing one interconnect helped that component, once I replaced all, there was a "sum is greater than its parts" effect. In my case, this lead me to change my Valhalla speaker cables to Sigma (latest version) and that too further elevated the sound quality, to the point that I realized I didn't need a better amp or speakers, which in reality would have cost far more than the cables!
I even found that switching my speaker jumper cable from Valhalla to Sigma made a significant difference.
At first, I suspected that the Sigma might be "bright" in the treble and perhaps "lean" in the bass. However, after break-in (perhaps 100 hours at most) and carefully listening to various LPs and digital albums, I feel that they are NOT bright or lean, but rather more revealing, less "forgiving". If the recording has the violins too harsh or bright, you will hear it. Bass is clean, full without any bloom and individual notes are definitely discernible if the recording is good. The loss of the bloom, the increase in separation may be interpreted at first as "lean", or less impactful, but the pedals of an organ are "felt" and each note of the bass chord is discernible. On a double bass, you can literally tell the difference in how the strings are "plucked". On guitars you can tell the type of string material. Detailed, yet still musical.
Granted, I listen only to classical and a little jazz-- no rock, metal, rap, etc. So, sound stage, separation of instruments, tonal character of the instrument, being able to enjoy technique as well as overall musicality, are important to me.
Importantly, I have a tube preamp and tube mono block amps. I suspect this would make a difference.
I too wish I could afford Omega speaker cables, but alas, they are just too expensive. I am considering upgrading a couple of my interconnects.
Incidentally, I found that from the Everest to the wall outlet, the Omega XC power cable was better than the Sigma XC power cable by about 20%, but again, remember I run my mono blocks off the Everest.
My system: Sonus Faber Il Cremonese speakers. AMG Viella turntable with JT tonearm, Soundsmith Strain Gauge cart and its proprietary phono amp, dCS Apex Rossini DAC, ARC Ref 6SE preamp and Rogue Audio Apollo Dark Mono amps.
