I've replaced 4 external $.035 fuses with 4 Isoclean fuses and within 48 hours I could not hear any difference whatsoever.
(In my experience, simple electrical and some line conditioners take about 48 hours of burn-in time.)
Several days later I replaced the 4 internal fuses on each rail of my amp. Within 48 hours the sonic improvements were about equal to going from audio grade wall receptacles to cryo-treated and higher audio grade wall receptacle. In other words, a very noticeable improvment.
A noticeable amount of graininess was gone and replaced with a richer, warmer, more detailed and pristine presentation. The improvements were well worth the money.
There is another fuse mfg'er called HiFi-Tuning.com that appears to produce an even better built and better materials fuse than the IsoClean. I've replaced that equipment and left the fuses in place (accidentally). This next round I'm going for the hifi-tuning.com fuses.
With regard to safety, there should be no difference. Safety and construction and blow are the sole purpose for a fuses existence and easily understood even by somebody like myself. An audio grade fuse simple replaces the very cheap alumimun and glass materials with silver, copper, gold-plating, and ceramic type materials.
There's probably more voodoo just by mentioning the subject.
The key to safety is replacing a fuse with an identical spec'ed fuse including amperage, size, and type( slow or fast blow).
-IMO
