DEVO 12s,... how does everyone like compared to 8s

'Worth the money' is a really hard thing to answer.
The Devo12 is a really nice system. The build-quality is better, it has 3-way switches all-around, and more controls than I know what to do with. The screen is brighter than the 8 (though honestly I've never compared them in full sunlight).
Be aware that I am not claiming that quality-assurance is any better on the 12 than any other radios. This is Walkera's main weakness. there are far too many reports of hardware failure, and the 12 does not seem to be an exception.

However, as far as capabilities go, with Deviation, the 12 won't really provide much new as far as capabilities go. Besides the additional controls, you'll get a real-time clock (not yet in Deviation trunk), and the bigger screen (but current Deviation trunk doesn't use it all yet).
It is currently harder to work with the filesystem (unlike the Devo6/8/10/12, the 'media' directory is not directly USB accessible), but I have a plan to address that.

I still do almost all of my development on my Devo8, but that is mostly because it is so hacked up, I don't worry about damaging it. However I personally like the Devo12 best of my Devo collection.

FYI, you can contact Walkera. I've heard of people getting replacement displays from them I think. If not, you could buy one and replace it yourself, though it requires unsoldering and re-soldering a ribbon cable which requires some level of soldering competence. You could probably do it for ~$20 though.