  Three versions of the quark-meson coupling (QMC) model are applied to
describe properties of nuclear matter and finite nuclei. The models differ in
the treatment of the bag constant and in terms of nonlinear scalar
self-interactions. As a consequence opposite predictions for the medium
modifications of the internal nucleon structure arise. After calibrating the
model parameters at equilibrium nuclear matter density, binding energies,
charge radii, single-particle spectra and density distributions of spherical
nuclei are analyzed and compared with QHD calculations. For the models which
predict a decreasing size of the nucleon in the nuclear environment,
unrealistic features of the nuclear shapes arise.
