I've been busy lately, so not much DF. I've got 4h running under linux, same as previous versions, and so far it runs fine.
There are still occasional crashes, seemingly more than I remember from the 3 series, but I tend to leave it running for days at a time - I now save/restart after major events, and the seasonal saves help a lot.
I'm looking for a way to get QT5 on my box - I'm running Gentoo, and they're not in the main portage line yet, and doing the overlays hoses other parts of the system - maybe I'll try The Ancient Way, by doing a straight install from tarballs into /usr/local. Then I can compile Therapist from scratch, and create an up-to-date MDF package for linux. The old 3a3 Therapist still runs fine.
In the meantime, I've struck galena-bearing rock.