Alternatives for converting MP4 to MP3 and editing?

Tue Mar 26 17:23:40 MST 2013

#1. What is the best/easiest/most-efficient way to
    convert an mp4 video file to an mp3 audio file?

#2. Is anyone using 'avconv'? What would a suitable
    syntax be to use that?  Or is there another
    command line option that is more efficient?

#3. What Linux tool offers the easiest/most-efficient
    way to edit (shorten) an audio file?

Today, I installed Sound Converter and it worked okay to covert a
sample file with '.ogg' as the default format, until I changed the
preferences to '.mp3' the result of which is a smaller file and more
universal.

 8228108 Mar 26 17:09 mbquando.mp4
 3176854 Mar 26 17:10 mbquando.ogg
 2565192 Mar 26 17:12 mbquando.mp3

Is there some significant advantage to the .ogg format?