ffmpeg or Lame

[Phazon]

Hi, first of all, I want to apologize for my English. It's not my primary language so I may make mistakes.

My question is simple.. When transcoding MP3 files (primary 320kbps MP3s that I transcode to 256kbps), should I use ffmpeg (thedefault config with Subsonic 4.7), or should I use Lame?

If I use lame, is lame -b %b %s - correct?