WMA is Windows' old house band: big in the early 2000s, mostly retired now. It was born in 1999, Microsoft, and its real weak spot is the modern world: Apple devices, browsers and most apps have moved on.
FLAC is the audiophile's handshake: CD-perfect sound at roughly half the shelf space. Free Lossless Audio Codec: think ZIP for sound: it decompresses back to the exact original. That makes it the right destination when what you need is archiving music with zero quality loss and a genuine size saving.