For anyone interested, I have been doing some research on both OSCE & OSWE, and here’s my general idea.
If OSCP is focused on pen testing, these two certificates are focused on exploit development and advanced attacks.
Generally, OSCE focuses on finding and crafting advanced vulnerabilities for linux and Windows. OSWE is the same but for web applicatios.
You can find the following excellent study plan for OSCE, which can help you understand what’s needed from you before registering for the course:
https://www.abatchy.com/2017/03/osce-study-plan
Personally, I have registered to Pentester Academy, and started taking their excellent courses on relevant topics.
Once I feel I’m comfortable on all topics, I will register for the OSCE course.
OSCP is not a requirement for OSCE, since it focuses on a slightly different area, though I would recommend doing it before OSCE. However, OSCP is a prerequisite for OSWE.
OSWE is still new “less than a year”, so not many topics and reviews are available on it.
I hope this helps some people 