So, imo, there are a few demos I have heard that are equal, if not superior to, the album version of the songs.
Again, as a musician, it's only my opinion. I have heard horrible demos, and some amazing ones full of feeling that is lost in the studio version.
I know the whole point in a demo is a demonstration of talent and songwriting: a songwriter/artists has a musical idea and sets it down/records it
either the best of his or her ability, or how he thinks it should be within the resources he has. Then, a studio picks it up and comes along, and
either has superior equipment and instrumentation to help either augment the artists song or intention, or attempt to control the final product
through the studio's sound as a means of marketing (aka profit).
On that note, I bring two demos I like more than the album version.