  We have performed a comparative analysis of three recent and reliable SnIa
datasets available in the literature: the Full Gold (FG) dataset (157 data
points $0<z<1.75$), a Truncated Gold (TG) dataset (140 data points $0<z<1$) and
the most recent Supernova Legacy Survey (SNLS) dataset (115 data points
$0<z<1$). We have analyzed and compared the likelihood of cosmological constant
and dynamical dark energy parametrizations allowing for crossing of the phantom
divide line (PDL). We find that even though the constraints obtained using the
three datasets are consistent with each other at the 95% confidence level, the
latest (SNLS) dataset shows distinct trends which are not shared by the Gold
datasets. We find that the best fit dynamical $w(z)$ obtained from the SNLS
dataset does not cross the PDL $w=-1$ and remains above and close to the $w=-1$
line for the whole redshift range $0<z<1$ showing no evidence for phantom
behavior. The LCDM parameter values ($w_0=-1$, $w_1=0$) almost coincide with
the best fit parameters of the dynamical $w(z)$ parametrizations. In contrast,
the best fit dynamical $w(z)$ obtained from the Gold datasets (FG and TG)
clearly crosses the PDL and departs significantly from the PDL $w=-1$ line
while the LCDM parameter values are about $2\sigma$ away from the best fit
$w(z)$. In addition, the $(\Omega_{0m},\Omega_\Lambda)$ parameters in a LCDM
parametrization without a flat prior, fit by the SNLS dataset, favor the
minimal flat LCDM concordance model. The corresponding fit with the Gold
datasets mildly favors a closed universe and the flat LCDM parameter values are
$1\sigma - 2\sigma$ away from the best fit $(\Omega_{0m},\Omega_\Lambda)$.
