  We reconstruct dark energy properties from two complementary supernova
datasets -- the newly released Gold+HST sample and SNLS. The results obtained
are consistent with standard $\Lambda$CDM model within $2\sigma$ error bars
although the Gold+HST data favour evolving dark energy slightly more than SNLS.
Using complementary data from baryon acoustic oscillations and the cosmic
microwave background to constrain dark energy, we find that our results in this
case are strongly dependent on the present value of the matter density
$\Omega_m$. Consequently, no firm conclusions regarding constancy or
variability of dark energy density can be drawn from these data alone unless
the value of $\Omega_m$ is known to an accuracy of a few percent. However,
possible variability is significantly restricted if this data is used in
conjunction with supernova data.
