Coincidentally, I have been swapping a 20uf ASC oil and 47uf/630v. Solen in my Cornet during the past couple weeks. Both are good sounding caps for power supply applications. For my tastes, the ASC is overall superior due to its nice midbass warmth and dynamics and smooth detailed sound across the entire spectrum. The Solen is somewhat faster and has more of a "hifi spectacular" sound. It is also leaner in the midbass (or is the ASC oil too warm?) and has, for lack of a better term, a mechanical plastic sound in the mids and treble. I can easily see someone choosing the Solen over the ASC, but my priorities favor the ASC.
Lastly, if you try the Solen, be sure to try hooking it up in both directions. It's non-polarized so you can wire it either way. It does sound different depending on which end is connected to the positive and which to the negative. Also be sure to give each cap adequate time for breakin. By reputation the ASC takes a fairly long time, 50 hours or so. I just left it powered up for a couple days before listening carefully, so can't comment on that myself. The Solen only took a few hours as I recall
Enjoy!
Dave
