I tend to be rather sceptical of metal bands making rerecordings, but I'd make Under Satanae by Moonspell a major exception to this. Since the original Anno Satanae and Under the Moonspell demos, which these songs had taken from, the sound of the band had radically transformed from a black metal-dominated sound (with influences of folk and gothic metal beginning to emerge on Under the Moonspell) to a much more predominantly gothic sound.
The genius move Moonspell make here is in not trying to recapture their early sound, but instead adapting these old songs to their new sound, slowing them down, teasing out the gothic and folk metal flourishes that had already been there, and adding further layers of gothic menace besides. The end result is a radical reinterpretation of the material in question which retains a little more black metal fury than was typical for Moonspell at this point in their career but at the same time presents a fresh and new look at these songs, so the rerecording does not feel redundant or unnecessary next to the originals. It's not quite an essential part of their discography, but only because the material they are building on here was when always rather rudimentary compared to their more developed works.
Memo to any other metal band contemplating a rerecording: don't bother unless it's at least a major departure from the original versions as this one is.