Install Developer-Version oder better nothing?

[Kunde]

Hey, have a Server running Debian and 2.6.21 Kernel. (and i won't install earlier Kernels)
For this Kernel there is only a grsec developer / testing version availible.

The question is now:
Install this developer version for a productive server or let the standard kernel running upto grsec final is out?

PS:
when will the final be released?