Apple has updated iTunes to version 10.5.2. The new updated has fixed some bugs of the previous version.
The new update has fixed an audio distortion issue when playing or importing specific CD types. iTunes 10.5.2 has also added improvements to iTunes Match service.
The update can be downloaded from the Apple Software Update Utility or as a direct download from the website.
Apple is vague on the improvements included to their iTunes Match service. If you notice any changes, please share with us in the comments section.