here's a little bit about me, and why i decided to build this: https://carbon.ms/#memo
re: sage, i'd say that sage is well-known as being a great general purpose accounting software for multi-location, and multi-entity businesses. but i don't know of many manufacturers running on sage.
re: erpnext, also great. i love their open source model, their developer ecosystem, and great documentation. i'd say the major difference is the data model and the UI that it begets. in erpnext, i think everything is a "doctype" where with carbon things are more bespoke. each ui has it's own specific tables, and specific ui
re: erp