Known Fixes, Features and persistent bugs of Mac OS X 10.5.2 are:

1. SMB/CIFS connections to some 3rd party servers can now be made from Finder. (This functionality worked in Tiger but was broken in 10.5.0 and 10.5.1.
   
   
   
2. DVD/CD Sharing is now available as an option in the Sharing Preferences.
   
   
   
3. 'Remote Install Mac OS X' now application in Utilities folder to install Mac OS X on the MacBook Air.
   
   
   
4. The icon preview for Microsoft Office 2008 documents seems to have been fixed.
   
   
   
5. The quick look of Microsoft PowerPoint 2008 documents seems to have been fixed. Previously, quick look only showed an icon.
   
   
   
6. Fixed an issue that occurred when users changed mounted hard drive icons (ctrl-i, paste new icon) and later could not revert to the original icon. 10.5.2 seems to have removed the error and allows users to revert to old icons.
   
   
   
7. Seems to have fixed how it handles ram usage by VMware Fusion. Previously, when quitting VMware while running Windows XP, the ram given to the virtual machine would remain as "inactive" for hours. Now, once Fusion is closed, the ram is no longer remains as "inactive" for more than a few minutes.
   
   
   
8. The way Mail.app handles threaded messages appears to be improved. Previously, when a new message arrived in the inbox and was part of a threaded discussion, clicking on the new message brought up a blank message. The work around was to click on an old message and then click on the new message. This appears to have been fixed.
   
   
   
9. When Caps Lock is mapped to Control on the MacBook Air, it appears there is no longer a delay before the control modifier becomes active. 10.5.2 does not appear to have fixed the same issue with the new aluminum apple keyboards.
   
   
   
10. Fixed crashing issue with Adobe CS2 & CS3 apps on non-Intel Macs when using any file browsing dialogue (save as, export, open, etc)
    
    
    
11. Fixed "Rename finder items" action in Automator which was broken in 10.5.0 and 10.5.1.
    
    
    
12. iDisk capacity and usage now correctly reported under the Finder
    
    
    
13. iDisk no longer consumes a behemoth amount of space on disk
    
    
    
14. Dictionary launch and load time greatly improved
    
    
    
15. iTunes album art screensaver fixed on C2D mbp and no longer has red tint when having more than 4 rows. The way the artwork is load is changed.
    
    
    
16. (Unverified) Graphics Update fixes sleep issues on older iMac G4 models, including the 800 MHz model
    
    
    
17. Fixed Bluetooth issue when awaking from sleep.

Also See:

Mac OS X 10.5.2 Possible issues