  The search for the Higgs boson(s) is one of the major priorities at the
upgraded Fermilab Tevatron and at the CERN Large Hadron Collider (LHC). Monte
Carlo event generators (MCs) are heavily utilized to extract and interpret the
Higgs signal, which depends on the details of the multiple soft-gluon emission
from the initial state partons in hadronic collisions. Thus, it is crucial to
establish the reliability of the MCs used by the experimentalists. In this
paper, the MC based parton shower formalism is compared to that of an analytic
resummation calculation. Theoretical input, predictions and, where they exist,
data for the transverse momentum distribution of Higgs bosons, $Z^0$ bosons,
and photon pairs are compared for the Tevatron and the LHC. This comparison is
useful in understanding the strengths and the weaknesses of the different
theoretical approaches, and in testing their reliability.
