I've started some testing and the only problem i found so far was right at the start, when updating the Core module
After trying to do an "update all modules", Core just stuck on "disabled" and I couldn't reload the config either
Error thrown on Core module update:
changing ownership of /etc/asterisk/http_custom.conf from root to asterisk apparently solved it and was able to update core and install all the other modules
Anything else i tried so far works well, the new modular UCP is a beast!