* The Elite-C repurposes the RAW pin for PB0, which makes it incompatible with a couple of keyboard PCBs out there that expect it to be VBUS power. Goldfish does not.
* It has a physical reset switch, which is almost as thick as the USB-Type C port. Goldfish is thinner here.
* Has a power LED like the Pro Micro (Version 2 onwards). Goldfish has no LED.
* The current version: version 3, has a bug that makes auto-detection of Master/Slave on split keyboards not work. Previous versions worked, and the bug is supposed to be fixed in version 4. (Edit: Fixed in version 3.1)
Goldfish should support this auto-detection with revision B onwards.