I bought some ARMsid chips from retrocomp and I like the resulting sound better than the swinsid nano but there is a slight price difference. You can hear the 2 compared on youtube (Adrian’s dungeon maybe?). Armsid is a more (not completely, but more) accurate sounding replacement. It’s also a smart chip which auto-detects the voltage at SID pin 28 (the pin which is normally at 9v or 12v on a commodore) which tells ARMsid whether it’s supposed to emulate an 8580 or a 6581, so anything 0-10v will model an 8580 and over 10v source to pin 28 it will model 6581.
In acknowledgement of the fact this thread is almost as old as the technology in question, this is only to contribute to future searches, I’m sure the original poster has already moved on but if not, retrocomp.cz has these in stock or aliexpress has been trying to sell me “genuine” sid chips for $30 lately but I just can’t seem to trust anyone selling me unobtanium for the price of a family sized pizza.