Flac to mp3 player

Sidetracked

I want to convert my some of my Flac concert files to mp3 so I can listen to them on my player... just wondering if anyone has any suggestions as to the best bitrate to use? The CDs I made with the flac sound great but the mp3's?...so far not so great.
I'm using a free converter called Switch and it let's you choose variable bit or constant bit...also gives you an output choice of stereo, joint, force and mono...if anyone knows what joint and force are I'd love to know that too.
Appreciate any advice.