  Here we discuss what are perhaps the two most popular variants of CDM that
might agree with the data: \lcdm\ and CHDM. While the predictions of
COBE-normalized \lcdm\ and CHDM both agree well with the available data on
scales of $\sim 10$ to $100 \hMpc$, each has potential virtues and defects.
\lcdm\ with $\Omega_0 \sim 0.3$ has the possible virtue of allowing a higher
expansion rate $H_0$ for a given cosmic age $t_0$, but the defect of predicting
too much fluctuation power on small scales. CHDM has less power on small
scales, so its predictions appear to be in good agreement with data on the
galaxy distribution, but it remains to be seen whether it predicts early enough
galaxy formation to be compatible with the latest high-redshift data. Also, two
very recent observational results favor high cosmic density, and thus favor
$\Omega=1$ models such as CHDM over \lcdm\ --- (1) the positive deceleration
parameter $q_0>0$ measured using high-redshift Type Ia supernovae, and (2) the
low primordial deuterium/hydrogen ratio measured in two different quasar
absorption spectra. We try to identify ``best'' variants of both \lcdm\ and
CHDM, and discuss critical observational tests for both models.
