[Nook HD, HD+ Android Development] amaces:
Heads-up that Wi-Fi display/mirroring still doesn't fully work on CM. The Chromecast sink is found now directly from the casting tile, and there are no user error messages, or even warnings, yet the screen remains blank. Audio is fine, as before. There are many possible causes, but my bet is all the QCOM changes to frameworks, etc.

P.S. This is probably a known fact, but I'l mention it anyways: while you don't need any dedicated casting app, Play Services (thus GApps) are required for this functionality.

Haven't really found anything obviously wrong connected to your issue, but I'll keep this in mind. There are so many developments in the OMAP4 world right now, so little time available, and I don't recall anyone else mentioning this problem. Now, you did wipe everything thoroughly, and tested things without GApps, or any other apps (bare ROM), right?

Getting flashbacks of junior high English… You certainly can, I guess you may, but you shouldn't ;) We discussed quite a bit the reasons for the temporary size increase. Testing with additional optimization flags yielded compressed images/ROMs that are 10 MB larger (roughly 15 MB decrease in /system free space). Current builds use normal build flags, which can fit OpenGApps nano without problems. Also, /system is read-only during normal use, so free space there has no bearing on performance.

Yes, there are some issues with Wi-Fi on Marshmallow, either due to supplicant, or its interaction with our WLAN drivers. Beyond CM's UI issues with selecting a known SSID in the notification shade (which should be fixed now), it seems to have issues with disconnects, and I haven't figured out why. My connection only becomes unstable when I reboot the wireless AP; maybe your signal is intermittently weak.

P.S. Try the latest builds; the device seems better at reconnecting after rebooting the AP, so maybe your mileage is better.

Yes, battery is not as good as on stock, but as [MENTION=4465268]TheHamPimp[/MENTION] mentioned, you should still get about a week of deep sleep, at least with the bare ROM. Play Services, enabling extra features (location reporting?), any extra apps will sap the battery pretty quickly.

Let's do a thought experiment: if no plans for that, would your situation change? Will you roll up your sleeves, and do the work that's required? Probably not, and had you read just a couple of pages back, you'd know that CM13 builds were planned during the weekend, once the monthly AOSP updates are fully integrated. Also, phrasing things with “last month” seems to imply the last builds were ancient, when in fact they were less than two weeks old. There are hundreds of hours that went into keeping these devices afloat, it takes many hours for clean builds to complete, and uploading half a gigabyte of combined ROMs doesn't just happen instantaneously.

About the official TWRP images, while ovation's is fine, they renamed some flags and the display in hummingbird's is translated by about half, so not very usable. They use the last official CM12.1 device trees and kernel, but maybe I can push fixes to their cloned repositories. Either way, my builds are OK since I have full control over that.