I am strongly advocating the FLAC file format which in my opinion is best file format for lossless audio.
The most common complaint that I get is that DJ:s don’t want to migrate to FLAC format because Pioneer CDJs do not support FLAC and they are unable to play their gigs.
There is a way to do file format conversions so fast that is a smooth part in DJ workflow. I am using Foobar2000 for doing this.
https://www.youtube.com/watch?v=KKtV9ZMSz_I