Last friday I updated my Mac to the latest release 10.5.2. The update was 180 Mb in size, quite large but definitely smaller to the expected "monstrous" size according to the rumors (or at least the power PC update is not "this" big; maybe the Intel version is larger).
Apparently this release fixes a lot of bugs but besides some changes in the User Interface (the option to turn off the transparency in the menu bar, more options for Stacks) it didn't seem like a great change. Unfortunately it isn't still supported the possibility to use Network Shared Volumes in Time Machine which apparently was a feature that should be official in 10.5.2. Anyway I just checked the web for that and found in the very interesting Volker Weber's blog a suggestion that allows you to backup on "unsupported volumes" like Network Shares. No hope anyway to use a FAT-32 USB drive (it still requires an HFS+ disk in this case).
In my first weeks with 10.5 it seems that my Mac is a bit slower so I'm not this keen on upgrading my wife's Mac which is a bit older than mine (1 Ghz G4 with 512 Mb of RAM). In particular some applications seems to perform worse, especially Firefox, that's why I'm using more Safari these days, which by the way is improved dramatically with these latest releases. For example all Gmail features seem to work: there is a minor weird behavior here on the WYSIWYG interface of Blogger, that is, it seems you can't cut from another application & paste in the Blogger Post form (you should switch to the HTML interface, do the paste and get back to the WYSIWYG form) but definitely this is a small issue. Great job WebKit team!