I build a few of these and what a buggers to build. Still one of them won’t operate as it should. The components are quite dense and prone to make mistakes. But when the do work it’s a nice ADSR. I would not recommend them just because of the poor layout of the pcb’s. I do have a few of them in my rack though.
https://github.com/erica-synths/diy-eurorack
Difficulty to build: Hard