@mr.smithster: FWIW, I think this is exactly right. Like others that have posted, I react to the silicone, and my ears get very itchy. This seems to increase cerumen production.
I dislike the discoloured, unhygienic appearance of silicone moulds, although I suppose it’s more of an aesthetic issue for me than a biological one… (My deceased father did, indeed, ferment ear cheese in his cavernous ear canals, reminiscent of the cheese ripening caves of France, however!)
I like the way the slippery acrylic moulds slide fairly easily into my sinuous ear canals, affording me an excellent acoustic coupling.
I recommend acrylic to posters who ask, but you’re right - it’s an entirely personal choice.