i have auditioned both the PAD 20th anniv contego PC and the shunyata anaconda alpha helix PC on my ux3-se. knowing that PCs tend to be highly component specific in outcome, my opinion is based solely on my cdp and within the context of my system.
i found similar results as per guidocorona on the esoteric he used in his comparison.
the PAD contego gave a greater evenhanded top to bottom presentation, slightly more authority, a bit more substance at the top end but not thick or veiled. more "gravitas" but not earthbound. no loss of detail compared with the anaconda.
the anaconda alpha helix [non vx] gave an excellent top to bottom sense but added a noticeable touch of top energy in comparison to the PAD PC. the top end didnt thin out with the anaconda, but it didnt subtlely flesh out the highs as did the PAD. in the context of my system, which has more than enough tweeter energy, this was not my goal.
speed may be a tad faster with the anaconda, clarity for both was excellent.the pad might have been given a blacker background. staging expanded a bit more with the PAD.
but, as guidocorona advised, you are placing the PCs on different components... cheers,marc