Finally going to merge Python3 support into the master branch of Joinmarket today :)
There should be a new release shortly that includes that, and coincurve (which will just make the secp256k1 binding a bit more reliable in terms of install, it's better maintained), and a few other fixes.
I'm also noting (being a relatively active user) that coinjoins are significantly more reliable after the random_under_max choosing algo introduced in 0.4. Yg bot seems to average about 20 txs/day (low fees).