  Total mass is arguably the most fundamental property for cosmological studies
with galaxy clusters. We investigate the present differences in the mass
estimates obtained through independent X-ray, weak-lensing, and dynamical
studies. We quantify the differences as the mean ratio 1-$b$=M$_{\rm
HE}$/M$_{\rm WL,dyn}$, where HE refers to hydrostatic masses obtained from
X-ray observations, WL refers to the results of weak-lensing measurements, and
dyn refers to the mass estimates either from velocity dispersion or from the
caustic technique. Recent X-ray masses reported by independent groups show
average differences smaller than $\sim$10$\%$, posing a strong limit on the
systematics that can be ascribed to the differences in the X-ray analysis when
studying the hydrostatic bias. The mean ratio between our X-ray masses and the
weak-lensing masses in the LC$^2$-single catalog is 1-$b$=0.74$\pm$0.06.
However, the mean mass ratios inferred from the WL masses of different projects
vary by a large amount, with APEX-SZ showing a bias consistent with zero
(1-$b$=1.02$\pm$0.12), LoCuSS and CCCP/MENeaCS showing a significant difference
(1-$b$=0.76$\pm$0.09 and 1-$b$=0.77$\pm$0.10, respectively), and WtG pointing
to the largest deviation (1-$b$=0.61$\pm$0.12). At odds with the WL results,
the dynamical mass measurements show better agreement with the X-ray
hydrostatic masses, although there are significant differences when relaxed or
disturbed clusters are used. The different ratios obtained using different mass
estimators suggest that there are still systematics that are not accounted for
in all the techniques used to recover cluster masses. This prevents the
determination of firm constraints on the level of hydrostatic mass bias in
galaxy clusters.
