Is mora.jp basically just a higher quality iTunes?

[BlazingAbyss]

Recently I noticed that the music sold on mora.jp were 320kbps AAC-LC files and if I recall correctly the ACC files sold on iTunes are only 256kbps.
Thus, (unless I'm missing something) if there's an album which is being sold on both sites, then you'd probably be better off getting it from mora.jp instead of iTunes, right?

Additionally, I've read that ACC files are superior to MP3 files, but I was curious as to how much better they actually were and whether or not they had any significant drawbacks.
Like, how well does a ACC file that's 256kbps (iTunes) or 320kbps (Mora) compare to a MP3 file that's 256kbps (Amazon) or 320kbps? (Google Play)