A thread has developed on the OSGeo email list (out of an “open source career” post in fact) asking how one can perform the same tasks using open source software as they do with ESRI.
Paul Ramsey as usual writes a spot on response to the question:
My general synopsis: for server-side, for scriptability, for automation, for web-based, open source wins for most use cases, given a technically savvy user; for ad hoc, for cartographic production, for a user who is used to a point-n-click experience end to end, proprietary still wins.
Nacho Libre – defender of open source
Spatially Adjusted 