This hides information and does not comply with verboseness policy, see http://devmanual.gentoo.org/ebuild-writing/common-mistakes/index.html under "Build log not verbose" In this particular case the --quiet option does not enable me to see where the cloning/pulling process gets stuck for example. It should be verbose by default.
+ 15 Mar 2013; Christoph Junghans <ottxor@gentoo.org> mercurial.eclass: + default to EHG_QUIET="OFF" (bug #461858) +