  Angular momentum, or spin, is a fundamental property of black holes (BHs),
yet it is much more difficult to estimate than mass or accretion rate (for
actively accreting systems). In recent years, high-quality X-ray observations
have allowed for detailed measurements of the Fe K$\alpha$ emission line, where
relativistic line broadening allows constraints on the spin parameter (the
X-ray reflection method). Another technique uses accretion disk models to fit
the AGN continuum emission (the continuum-fitting, or CF, method). Although
each technique has model-dependent uncertainties, these are the best empirical
tools currently available and should be vetted in systems where both techniques
can be applied. A detailed comparison of the two methods is also useful because
neither method can be applied to all AGN. The X-ray reflection technique
targets mostly local (z $\lesssim$ 0.1) systems, while the CF method can be
applied at higher redshift, up to and beyond the peak of AGN activity and
growth. Here, we apply the CF method to two AGN with X-ray reflection
measurements. For both the high-mass AGN, H1821+643, and the Seyfert 1, NGC
3783, we find a range in spin parameter consistent with the X-ray reflection
measurements. However, the near-maximal spin favored by the reflection method
for NGC 3783 is more probable if we add a disk wind to the model. Refinement of
these techniques, together with improved X-ray measurements and tighter BH mass
constraints, will permit this comparison in a larger sample of AGN and increase
our confidence in these spin estimation techniques.
