  The precise determination of global properties of galaxy clusters, and their
scaling relations, is a task of prime importance for the use of clusters as
cosmological probes. We performed a detailed XMM-Newton study of 14 X-ray
luminous REFLEX Survey clusters at z~0.3. We found that the properties of the
galaxy clusters show a self-similar behavior at r>0.1r_{vir}. This helps to
establish tighter scaling relations. Peculiarities in the individual clusters
are important to understand the scatter from the self-similar frame in the
cluster central parts.
