It's all about the mastering or remastering. I just got a bunch of Japan Remastered Virgin Vinyl, for my jazz collection, and they're like butter compared to the originals.

That's what you should be looking for(mastering). There's no difference between 320 and FLAC for everyone except for that one odd person who has genius ears.

I say enjoy your music. No fun in picking the music apart, trying to find a little nothing between lossy and lossless.