Yeah. One thing I'm wary about though is developing blind spots due to a) knowing Erlang and OTP very well and b) knowing rebar3 itself very well.

I'm sure there are plenty of tricky traps that regulars have learned to work around and "just know how to use it without breaking it"; I have a suspicion a lot of unsatisfied people are those who come with different expectations of what the tool should do and how it should behave.

In these cases, they'll have a frustrating experience. I'd be interested to learn what it is so that we can make the whole thing better.