Version 1.4.0 was released on July 24, 2009. It does actually have some compelling features that aren't in 1.3.x: http://postgis.refractions.net/news/20090724/ Note that (>=sci-libs/geos-3.0) and (>=sci-libs/proj-4.5), previously optional via USE flags, are now required, as is (>=virtual/postgresql-server-8.2).
I'll 2nd this. I have moved on past postgresql 8.2 on production.
+ 19 Sep 2009; Patrick Lauer <patrick@gentoo.org> +postgis-1.4.0.ebuild: + Bump to 1.4.0, fixes #284733