El equipo de Gentoo Portage acaba de sacar la versión 2.1, entre las mejoras que se han realizado se encuentran:

* FEATURES="confcache" integration; global caching to speed up configure calls,
requires dev-util/confcache
* elog framework and accompanying modules for logging ebuild warnings, errors
and general notices. Collects eerror/ewarn/elog/einfo messages.
* New elog function (should replace einfo in many cases)
* version syntax enhancements allowing multiple suffixes and a new 'cvs'
prefix for denoting "live sources" ebuilds.
* config files as directories enabling more flexible settings management.
* Addition of an register_die_hook method that allows ebuild/eclasses to
register functions to be called for better debugging on errors.
* Addition of pre and post user hookable functions for each ebuild phase, accessible
via portage bashrc. Example would be pre_src_unpack .
* cache refactoring- runtime improvement from 35% -> 65%.
* Intelligently handle and display USE_EXPAND-based IUSE variables.
* FEATURES="parallel-fetch". Download in parallel to compilation.
* Include a "changed or new" USE flag output when --verbose isn't specified.
* Support for splitting out debug information into separate files in
/usr/lib{,32,64}.

http://www.preguntaslinux.org/showthread.php?tid=1858