Recommended FLAC converter? - Divisions by zero

I have a collection of music in flac format and now I want to store them on my phone. flac files get too much space and downloading all the playlist in mp3 takes as much time as finding decent and real high quality flacs (there is plenty of songs on internet which only look like 320kbps and are not really high quality). So I decided to convert my flac files into mp3 with and I prefer minimum amount of quality loss; what is the best software for it? - Doesn’t matter if conversion take some time if the quality would be decent.