Finding information on this topic isn't easy at this site. Looking at Foobar 2000's site, they seem to have that information right on the home page, and I'd like to know how MC competes with that (I'm assuming that the information on Foobar's site is part of the product and not an ad...the stuff concerning dBpoweramp is what I have in mind.
For the CD ripper in the Foobar suite, it reads:
"Digitally rip audio CDs, securely AccurateRip verified error free".
From what I've read, it compares your rip with others and lets you know whether your rip is error free. I like the sound of that. Does MC do the same? Also, suppose that Foobar's ripper does spot that your rip has errors. Then what? Are you stuck with an inaccurate rip, or can you get an error free version of that song somehow? If the latter, how?
MC's ripper can rip in secure mode, verifying its read several times to confirm that what it reads is correct. It creates a log to let you know that the rip was error free. It does not compare against a database like AccurateRip. Read errors are rarely ever the same when you read over the same part over and over, so when it comes back the same several times in a row you can be pretty sure its correct. That's the idea, I think at least. I have ripped difficult CD's with different programs in the past and my finding was that once a CD is unreadable, its unreadable with any ripping program. Some are faster than others though, but unreadable remains unreadable and there's no magic to make it work, other than cleaning or trying to remove scratches.
Short of downloading from the internet somewhere or buying another CD, there is no way to get the music on a damaged CD. Maybe there are repair programs but I wouldn't trust those to be honest. It will never be 100% accurate. So ripping programs will tell you it failed or is only 98% accurate. And then nothing. Try cleaning the CD, remove a scratch if that's the problem and try again. Not much else to do, really.
The Foobar suite also mentions removing duplicate copies of songs etc. from your collection. Does that mean that if a song is removed from Album A, you can still hear that song on Album A, so long as you have another album with the same song on it?
You should really ask this on the Foobar forums.
On the other hand, curious how any suite would handle various versions of the same album, e.g. The Stooges' "Raw power", which has a David Bowie mix, as well as an Iggy Pop mix, as well as one more, from memory. I wouldn't want to lose legitimate different versions!
A duplicate isn't a duplicate unless its the same version. Let's say you have the best of Elton John and it contains a couple of songs from a studio album you have as well. Same song, same length, identical in any way. That's a duplicate. MC doesn't remove duplicates, but it can help you find them using smartlists and expressions. If you want to delete them, its up to you. Once you delete the version from the best of album, then its gone (suprise). If you want to listen to that song you'll have to play it from the other album, but you can't listen to the complete best of album including the song you deleted, unless you manually add it from the other album. Before you ask, MC cannot somehow deduplicate your library and create softlinks in place of the deleted track (I don't know but I don't think Foobar does that).
The problem as I see it however is that often duplicates are not quite the same. One if often mastered slightly differently, is more compressed than the other, etc etc. Personally, I don't bother trying to figure out which is the best and which to delete, as it doesn't gain much anyway. It will leave incomplete albums and I don't like that. A typical song is what, 50MB in lossless? How many duplicates would you have? I don't know about other people's library but I suppose if its more than 10% its weird. I get maybe a few percent of duplicates .. see what I'm getting at here? My library is 1TB, if I can free 5GB at most ... so what? It's not worth the fuss. Storage is too cheap to waste the time to figure it out. But that's my idea at least.