Here's my experience using the updater with 3.2.1
- Installing a previously uninstalled plug-in
Mostly works, but "enable plug-in" link always reports there's a "bad header". Enabling plug-in from main plug-ins page works.
- Updating an existing plug-in
Fails fairly badly - old plug-in is replaced with an otherwise empty directory containing one empty directory. No update is performed, and plug-in ceases to be accessible from plug-ins page. Only way around it is to actively delete old plug-in and install from scratch.
EDIT: Just realized this system posts bug reports on a random forum! Sorry! This bug report refers to the behaviour of the sftp updater plug-in (http://wordpress.org/extend/plugins/ssh-sftp-updater-support/)