With inspiration from Meloeth's Instant Health addon, cncfanatics has coded a new addon called LibQuickHealth that provides exactly the same function, but improves on it in more than one way. Not only is it a library that does not replace the default UNIT_HEALTH event but adds to it instead, providing health updates from both the combat log and the default UNIT_HEALTH update, but it is also modular. In addition, there is less of a performance hit, as it takes less code and doesn't force-call updates to the frames. Unit frame addons that don't support it (yet) will not show the updates with the lib installed, but once the appropriate module is installed, they will use the library to update health. In addition, it is fully compatible with the default Blizzard frames and does not cause taint.
Currently supported unit frames are Grid, Pitbull, oUF, x-Perl, PerfectRaid, sRaidFrames, and the default Blizzard frames. They have all been tested and are error-free. The library, as well as all modules, can be acquired from the wowace site.
Modules:
Blizzard default UI
Pitbull
Grid
sRaidFrames
PerfectRaid
oUF
Just needs the library:
x-Perl
ag_UF support will be coming soon.
The original thread on the wowace forums is here:
QuickHealth