Since we have migrated our code base to Symfony 1.4, we have noticed that it is really slow when deploying projects, compare with running rsync command directly from the command line console.
The Symfony framework forum
suggested that on line 334 of http://trac.symfony-project.org/browser/branches/1.4/lib/task/sfFilesystem.class.php
there is code
and if commented out the problem will be gone.
Someone has already created a ticket http://trac.symfony-project.org/ticket/8877
for the Symfony team to fix.
Hopefully they can get this fixed soon as it really takes a while when deploying projects and will break sites before deployment finishes.