It has many many python3 crash bugs, especially on the MWS side. I have had an open PR for like a year to fix one of them, and it has been ignored.
This makes me not very hopeful that being on the list means anything.
(I am exclusively python3, but I have to wrestle with this a fair bit still)
Be wary adventurer, while boto3 is super neat and a python3 treat, there unsteady footings beneath your feet (api differences).
Until it does, either boto should be "fixed", or perhaps the MWS piece spun off.