I haven’t tried any custom roms on my FP4. But I can say I wholeheartedly support their work. Maybe the older ones had issues, but mine has been running smoothly ever since I bought it when it launched.
I’ve also dropped it like 200 times already, and haven’t a single crack. The back cover is cracked though, but that’s because I took it off so often to show people :P
All in all, 10/10.
I actually like this, at least in some way it could lower the barrier for actually explaining what a function does. Though I don’t see this working in an office environment