Um, .wav is a lossless format. It's just raw PCM with no compression. An upscaled FLAC from a lossy source is not lossless, even though it's stored in a lossless compatible format (FLAC). A properly encoded and compressed MP3 file will sound very close to the lossless source, but when procuring those lossy files from third parties, you rely on whoever compressed them doing it properly. I prefer to store my music repository in a lossless format, and stream/sync in lossy.
Um, .wav is a lossless format. It's just raw PCM with no compression. An upscaled FLAC from a lossy source is not lossless, even though it's stored in a lossless compatible format (FLAC). A properly encoded and compressed MP3 file will sound very close to the lossless source, but when procuring those lossy files from third parties, you rely on whoever compressed them doing it properly. I prefer to store my music repository in a lossless format, and stream/sync in lossy.