  Continuum and lattice methods are used to investigate systematic issues in
the sum rule determination of $V_{us}$ using inclusive hadronic $\tau$ decay
data. Results for $V_{us}$ employing assumptions for $D>4$ OPE contributions
used in previous conventional implementations of this approach are shown to
display unphysical dependence on the sum rule weight, $w$, and choice of upper
limit, $s_0$, of the relevant experimental spectral integrals. Continuum and
lattice results suggest a new implementation of the sum rule approach with not
just $\vert V_{us}\vert$, but also $D>4$ effective condensates, fit to data.
Lattice results are also shown to provide a quantitative assessment of
truncation uncertainties for the slowly converging $D=2$ OPE series. The new
sum rule implementation yields $\vert V_{us}\vert$ results free of unphysical
$s_0$- and $w$-dependences and $\sim 0.0020$ higher than that obtained using
the conventional implementation. With preliminary new experimental results for
the $K\pi$ branching fraction, the resulting $\vert V_{us}\vert$ is in
excellent agreement with that based on $K_{\ell 3}$, and compatible within
errors with expectations from three-family unitarity.
