In my experience with Suno ($40 spent so far) sound quality is worse than the cherry picked examples from Udio - especially the vocals - but everything I've heard from Udio could best be described as the elevator music equivalent of their respective genres so that's probably why it sounds so good. There seems to be a real quality vs originality trade off in the state of the art.

That said, I've only had the chance to generate a few songs with Udio and they have all sounded like they were recorded by a prison band in an overcrowded cell (I create mainly instrumental/orchestra/sound track music).