Best lossless ripping for Mac Options

[Sabeque]

Hi,

I've done a lot of searching on this topic and links keep pointing to this forum, so I believe the people here know their stuff.

I apologize if this has been already addressed. I see similar questions and threads but not one for my specific situation. A lot of the data out there also seems to be very subjective, overwhelming and/or confusing. I also apologize for all of the info but I want to be thorough.

Objective:
Rip CD collection in highest quality possible to lossless format (as yet undefined).

Factors:
~ I'm on a Mac and from what I've read XLD is the best option for accurate rips.
~ I want to be able to tag my files with Artist, Track name, etc. and want compatibility with iTunes without plugins or workarounds, so FLAC is not an option for me.
~ My music is mostly electronic and hip hop (not sure if this makes a difference when choosing the lossless format or conversion settings).
~ Larger file size is not a concern for me. Quality is. HD space is cheap.
~ Many of my CDs are mixed, i.e. gapless.

Purpose:
~ To have the highest quality digital backup possible. Many of my CDs are rare or irreplaceable promos. A few are also older and have begun to degrade. I want to convert everything now in the best quality I can so that I can save my music indefinitely.
~ After the CDs degrade more I need another source as close as possible to the original. Therefore I want to have lossless files that I can listen to or use whenever I need to create a lossy (MP3) version for my iPhone.

Questions:
~ When trying to convert some CDs in iTunes, some tracks were not converted at all because the CDs were degraded (no scratches, just old). I am hoping XLD can use error correction to "fix" these issues. Does XLD do this kind of correction?
~ I have heard ALAC may not be a good choice because of a theoretical "jitter" issue which compromises quality. Is this true?
~ Assuming AIFF is the best choice based on the factors above, what would be the best settings? I see a lot of tutorials for FLAC conversion but not for AIFF. When I checked the Wiki page comparing lossless formats I also did not see any AIFF reference there.
~ XLD has an option that says somethign about C2 error pointers (if your dirve supports this). How do I know if my drive supports this?
~ If you rip a gapless CD to multiple lossless tracks and then later convert those lossless files to mp3, can you join the tracks as one file when converting to mp3 so that you can remove the gaps? I've had problems playing gapless albums as multiple tracks in mp3 format on my iphone.

Thanks!

[Sabeque]

Thank you all very much for your insights and quick responses. I really learned a lot here and I appreciate everyone's input. This is good stuff to know!