  We use our resummed quantum gravity approach to Einstein's general theory of
relativity in the context of the Planck scale cosmology formulation of Bonanno
and Reuter to estimate the value of the cosmological constant such that
\rho_\Lambda=(0.0024 eV)^4. We argue that the closeness of this estimate to
experiment constrains susy GUT models. We discuss in turn various theoretical
issues that have been raised about the approach itself as well as about the
application to estimate the cosmological constant. Given the closeness of the
estimate to the currently observed value, we also discuss the theoretical
uncertainty in the estimate -- at this time, we argue it is still large.
