Another observation after installing stuff today:
A while back I found out that Mate was't handling two monitors very well, and that hasn't changed with 4.1. My dev machine has two large monitors, one connected to VGA and the other connected to HMDI., I haven't been able to configure the displays. The wrong one is my primary display, and when I try to change that, the display settings dialog behaves badly. (The bad behavior is hard to describe, but if this is new information, I'll try to let you know more.)
After attempting to configure the monitors, one of them , one monitor displays garbage at the top of the screen, and is blank otherwise. I don't actually plan to use Mate on that machine, so it's not going to be a big problem for me, but I thought I'd mention it once more.
(I have Budgie, Mate, and Plasma installed on three SSDs that can be hot-swapped to boot that machine accordingly.)