I have devoted 1,000s of hours running in and listening to capacitors from all over the world most recently several are from very good to Excellent the new Clarity Copper S.A. cap gets my nod for best balanced capacitor at a very reasonable price. For money's not that much more then Solen these are very well balanced with a slightly warm character.
Next would be the Obbiggato Gold cap slightly warmer still a bit on The rich side very close to a Mundorf Supreme for less money.
The Big shock to this final cap was a total shocker. Sizes only .33uf
To 3.3. The Fostex, caps from Japan they are Copper foil, as well
As Tin foil. Using their own formula dielectric. In my new Martin Logan 11--A they will let you know exactly what is not right
I replaced stock with Clarity Csa and Mundorf Supreme 4.7,and 5.6
Caps put .33 fostex, on them, had Mundorf Silver oil bypass,
I only put the 3.3 on low voltage in my DHT preamp.
I know 2 others who use these. The are exceptional ,very natural
With tons of air around the instruments Bass noticeably better then Any Mundorf. I think these are magical with the clarity and or Mundorf Supreme I recommend 10% or better with the Fostex,
They can go toe to to with any cap the Duelund Cast is the Only
Cap I have found that us slightly better.
I have heard these in several settings,and now my own preamp
And Loudspeakers the engineers from what I was told spent 2 years on these the combination of Copper and specific amount of Tin foil totally hit a home run . No more expensive then a good Mundorf cap. It proved to me sometimes looking at a well kniwn name ,known for their Drivers was worth checking out.
It is too bad they are limited in sizes .madisound seems to be the only sourse.