You'd know better than me.
Yeah, even a 5% defect rate is pretty spectacular by all standards.
I dropped out of the scene right when the BleepBloop cart was being developed, and came back after it had all fallen apart and they were off the market, but I understand those were like a 20-25% defect rate?
EMS is pretty alright by me, I have two that are working fine, and I've only ever corrupted them by trying to run the PIXELH8 programs that only run on PROM out of their flash memory.
Complete Tangent: How hard are the repairs required on the dead stock BleepBloop carts you have? I'm curious because I like getting cheap broken stuff and fixing it for fun, but I recall them being non-USB, and I don't have a transferrer…