MISHA  You may want to contact the developer directly with your issues:

http://www.davtri.com/index.py/contact  
(Version 1.7.3)

PINKNEZUMI  *weren't repeated, sorry for the mistake.  
(Version 1.3)

ANONYMOUS  Yes, iSweep launches iTunes if it isn't already running, then closes it. This forces the iTunes Database to flush to make sure that it is up to date before performing any searches against it.  
(Version 1.3)

ANONYMOUS  The application also allows backing up and or deleting of duplicates once registered.   
(Version 1.0)

ANONYMOUS  Because iTunes 4.7 only compares Track Name and Artist, no other options. So if you have multiple songs from different albums, but with the same title, iTunes says they're duplicates, even when they're not. iSweep allows a much more controlled search. iSweep also allow deleting of duplicates and Backing-up of duplicates to a user chosen directory, which iTunes doesn't.  
(Version 1.0)

ANONYMOUS  Big deal. If you show the proper headers in iTunes you can see that for yourself.

This app is not worth the shareware fee.  
(Version 1.0)

ANONYMOUS  Just because you can see the headers doesn't change how iTunes determines if a file is a duplicate. If you are looking at trying to clean out hundreds of duplicates, then iSweep is well worth the cost. Not to mention that you can backup the duplicates, which iTunes does NOT allow. As to being worth the cost or not, you are entitled to your opinion, but that is all it is, your opinion. I asked around for a couple of weeks before settling on $15.00, which was more or less the adverage of what people suggested. I was thinking along the lines of $9 or $10 until I asked several people and got their responses.  
(Version 1.0)

ANONYMOUS  The point about showing the headers is that it will let you determine whether or not you want to delete the song (i.e. verify if it truly is a duplicate)

Anyone who knows their way around the Finder can back up their duplicates. Even the Finder's Search function and some proper sorting work just as well. And the Finder is free.

Prior to iTunes v4.7, this utility may have had value, however, in my opinion, no iTunes integration and the new Duplicates feature in v4.7 make this utility obsolete.  
(Version 1.0)

ANONYMOUS  The application was actually developed before 4.7 was released, but was not posted for public download due to needing to set up a payment authorizer and to complete testing.

And while you could go through the preferences for tracks one at a time, then track them down in finder, one at a time, this would not be at all practical if you have a lot of duplicates. I mean, could you see yourself doing that for hundreds of songs (or in a friend of mine's case, thousands of songs due to accidentally importing his library multiple times from a backup)? I couldn't. If you have enough music, that could take days. This app isn't meant for everyone, just those who have a lot of duplicate music files. Also, the lack of iTunes integration is due to the fact that Apple only has a visualizer plug-in architecture for iTunes. They never provided a standard plug-in api. And even if they did, why would you want a utility app to be running every time iTunes was opened, thereby using up resources for no reason? Personally, I only want a utility to be running when I actually need to use it.  
(Version 1.0)