  We consider the condensation energy, $E_c$ of strongly coupled,
magnetically-mediated superconductors within the context of the spin fermion
model. We argue that although experimentally obtained values of $E_c$ are of
the same order of magnitude as would be expected from BCS theory in optimally
and overdoped cuprates, this agreement is coincidental. The actual physics
behind the condensation energy is much richer. In particular, we argue that it
is vital to take both the fermionic and bosonic contributions to the
condensation energy into account when considering such materials, and that it
is only the sum of the two contributions $E_c$ which has physical meaning. Both
the experimental and our theoretically calculated condensation energies exhibit
a {\it decrease} with further underdoping past optimal doping, e.g. in the mid
to strong coupling regime. Below optimal doping, the physics is qualitatively
different from BCS theory as the gain in the condesation energy is a reult of
the feedback on spin excitations, while the fermionic contribution to $E_c$ is
positive due to an "undressing" feedback on the fermions. We argue that the
same feedback effect accounts for a gain in the kinetic energy at strong
coupling.
