  A central aim of materials discovery is an accurate and numerically reliable
description of thermodynamic properties, such as the enthalpies of formation
and decomposition. The r$^2$SCAN revision of the strongly constrained and
appropriately normed (SCAN) meta-generalized gradient approximation (meta-GGA)
balances numerical stability with high general accuracy. To assess the
r$^2$SCAN description of solid-state thermodynamics, we evaluate the formation
and decomposition enthalpies, equilibrium volumes, and fundamental bandgaps of
more than 1,000 solids using r$^2$SCAN, SCAN, and PBE, as well as two
dispersion-corrected variants, SCAN+rVV10 and r$^2$SCAN+rVV10. We show that
r$^2$SCAN achieves accuracy comparable to SCAN and often improves upon SCAN's
already excellent accuracy. Whereas SCAN+rVV10 is often observed to worsen the
formation enthalpies of SCAN, and makes no substantial correction to SCAN's
cell volume predictions, r$^2$SCAN+rVV10 predicts marginally less-accurate
formation enthalpies than r$^2$SCAN, and slightly more-accurate cell volumes
than r$^2$SCAN. The average absolute errors in predicted formation enthalpies
are found to decrease by a factor of 1.5 to 2.5 from the GGA level to the
meta-GGA level. Smaller decreases in error are observed for decomposition
enthalpies. For formation enthalpies r$^2$SCAN improves over SCAN for
intermetallic systems. For a few classes of systems -- transition metals,
intermetallics, weakly-bound solids, and enthalpies of decomposition into
compounds -- GGAs are comparable to meta-GGAs. In total, r$^2$SCAN and
r$^2$SCAN+rVV10 can be recommended as stable, general-purpose meta-GGAs for
materials discovery.
