The io9 item indicates that this extended version is actually shorter than the original, with multiple scenes or specific lines of dialogue cut entirely.
But perhaps the film is due for a bit of a reappraisal, as an upcoming rerelease of the original trilogy has promised a recut version of the third installment.
For principled completists, it may be interesting to examine, but this doesn’t really sound like a convincing selling point for the upcoming rerelease.
As far as new material goes, there’s not a whole lot to speak of beyond the reinstating of Christopher Young’s score.