  Aims. We measure, as far out as possible, radial temperature profiles for a
sample of ~50 hot, intermediate redshift galaxy clusters, selected from the
XMM-Newton archive, keeping systematic errors under control.
  Methods. Our work is characterized by two major improvements. Firstly, we use
the background modeling, rather than the background subtraction, and the Cash
statistic rather than the chi square; this method requires a careful
characterization of all background components. Secondly, we assess in details
systematic effects. We perform two groups of test: prior to the analysis, we
make use of extensive simulations to quantify the impact of different spectral
components on simulated spectra; after the analysis, we investigate how the
measured temperature profile changes, when choosing different key parameters.
  Results. The mean temperature profile declines beyond 0.2 R_{180}; for the
first time we provide an assessment of the source and the magnitude of
systematic uncertainties. When comparing our profile with that obtained from
hydrodynamic simulations, we find the slopes beyond ~0.2 R_{180} to be similar.
Our mean profile is similar but somewhat flatter with respect to that obtained
by previous observational works, possibly as a consequence of a different level
of characterization of systematic effects.
  Conclusions. This work allows us not only to constrain with confidence
cluster temperature profiles in outer regions, but also, from a more general
point of view, to explore the limits of the current X-ray experiments (in
particular XMM-Newton) with respect to the analysis of low surface brightness
emission.
