You still should note that this is an alpha version and for Lollipop on ARMv7+ devices only.
The most important issue at the moment seems to be the incompatibility with Samsung stock ROMs, especially because it's leading to boot loops. Rovo89 has been working hard on fixing this in the days since the first release, however it's not just a single spot that needs fixing.
Early testers should keep in mind that at the moment there isn't any uninstaller ZIP in case you run into a bootloop. And development will take some time... so do not expect to get a stable release after a few days. There is still huge load of changes that needs to be done.
Official thread: forum.xda-developers.com
Existing blog post: ShellScreen
