I used have some no-name polypropylene film & foils in my Parasex amps, 10uF after the rectifier and 15uF after the choke: these were fine for years with my 93db World Audio Design Speakers.
When I upgraded to Lowthers (97db) the power supply hum became audible so I swapped the 15uFs to some 47uF Mundorf Tube Caps. In comparison to the fast film and foils they sounded clouded and muddy. Wasn't at all impressed, even after some running in. Found some 1uF film and foils in my bits bin and strapped them across the Mundorfs - then the sound snapped back into focus.
I would really have liked a pair of Black Gates (space is too limited for 47uF film & foil) but I abandoned the search after a few weeks. (Anyone know why they stopped making them? There still seems to be the demand.)
Sorry, back to the topic. Yes, I'd recommend the Mundorf caps but only with a little help from something "faster".
John
Amateur Audiophile and Backstreet Boffin.
Original Foreplay with C4S + Sweet Whispers
ParaSEX amps with MQ nickel-cored outputs
Factory-built Lowther Acousta 115s with silver-coiled DX3s, wired in DNM solid-core
KEF active sub (help for the last couple of octaves).
Bottlehead DAC on batteries.