This is user friendly with a fair price.

Here is what I did.

If you pick thousands of songs at a time that will be too much.

1. Go to itunes and under the file menu select show duplicates
2. launch iDupe and set prefs
3. Click on the first song then scroll down and shift click on the last song in the block.
I picked 200 at a time I may have done 500 at times too.
4. Click refresh itunes selection
5. click scan for dupes
6. I looked over the the selected ones in iTunes.
When you lick on the last option in step 3 it will remove all the unchecked itunes songs
so i like to go through the list to make sure it looks ok before i hit the last option in itunes
Then i just do something else while it deletes the unchecked songs that are dupes.
In prefs i selected to keep the higher quality bit rates. If you put your curser on the option it will pop up telling you what each option does. I like this one because it has an option to keep the higher quality songs and delete the lower quality. There are other dupe removal programs that cost 30 bucks that don't even have that option.