Hi arcol, if you mean the 'lid-close settings' to chose between (screen off / low power / shut down) (?) then these seem to work just fine. You seem to have to reboot the first time you enable it (say first time choosing low power rather than just screen off) but thereafter any choice you make on the fly will apply as soon as you shut the lid.
I don't find the intended charging behaviour is working at all in my case though, unless there is again something that needs activating first I have missed in the menus.
In terms of it being buggy : (HF5 for me was totally unusable via NAND or multiple SD cards and re-installations, rendering all PND's usually unmountable, despite both PND run.sh versions and PNDstore PND useage would entirely wipe out the OS partition or NAND installation, so I stuck with HF4)
I was finding HF6a4 great to start with but there is a delay with the menu after exiting PND's as ESN raised. Chromium regularly has pages die and need killing (probably sortable by a fresh appdata folder for Chromium) and I am now getting occasional PND run Mounting errors, which if they occur, stop all other PND's from mounting thereafter until I reboot. Which isn't great when it occurs (could be SD card related but it happens on a variety of cards). Plus the charging script not working in my instance.
Otherwise and for an alpha release, it is very good and a massive improvement in my case over HF5 and HF4. The useability and functions of Pandora are getting better all the time, as is the software library growing daily with useful tools/games etc. Eventually it will all be an easy experience for anyone, with tons of stuff to lose time with.