"Why would anyone need another CD ripper / MP3 encoder frontend?"

Jack has been developed with one main goal: making MP3s without having to worry. There is nearly no way that an incomplete rip goes unnotices, e.g. Jack compares WAV and MP3 filesizes when continuing from a previous run. Jack also checks your HD space before doing anything (even keeps some MB free).

Jack is different from other such tools in a number of ways:
    * it is written in python
    * it is very configurable, maybe too much
    * it doesn't need X (but is better with it)
    * it can "rip" virtual CD images like the ones created by cdrdao
    * when using cdparanoia, cdparanoia's status information is displayed for all tracks, so you can see if something went wrong (I consider this very important - no one wants uncorrected errors or skips to go into one's MP3s. 'Tis the main reason why I don't use something beautiful like grip)
    * it allows for overlapping ripping / encoding: when the first track has been ripped, it's encoder is started as well as the second track's ripping process, this "read-ahead" is of course configurable, you can have it read the whole CD and start with the next one as the first one is beeing encoded
    * in on-the-fly mode, no WAVs have to be created, less space is wasted. I only recommend this if your encoder is nearly as fast as your ripper.
    * it uses sophisticated disk space management, i.e. it schedules it's ripping / encoding processes depending on available space. Jack tells you if the batch will not fit on your HD. If you want, you can have it choose the optimal sequence of tracks - great if you're low on HD space
    * freedb query, file renaming and id3 tagging - I know that this alone is not special, but Jack tries hard to recognize artist and title when working on a "Various Artists"-CD, so that the ID3 tag can be set correctly.
    * it can resume work after it has been interrupted. If all tracks have been ripped, it doesn't even need the CD anymore, even if you want to do a freedb query. In practice, this means that you can change the CD and start another instance of Jack.
    * it can do a freedb query based on MP3s alone, like if you don't remember from which CD those MP3s came from.

Of course, all other "obvious" features are included, too:

    * being GPL'ed
    * different rippers and encoders are supported
    * freedb submissions
    * proxy support via http_proxy environment variable (e.g. export http_proxy=http://cache.sld.tld:3128/)

I really like its features... but will there be a graphical version/frontend? I prefer things the graphical way

then we need Kjack