Now this is truly interesting. I have the original VHS. I had been a fan since 1999 and the Purple Rain tour was once of my first concerts (preceded only by Rush and Yes I think). I then bought the Purple Rain deluxe version to get CD versions of extra tracks like Erotic City, the full length Let's Go Crazy, Irresistible Bitch, etc., plus the concert on DVD. How much better is this DVD version?
Much, much better than what existed before. They recently found the original audio multi-track tapes of the concert in the Vault. That's why they decided to release a new version of it.
The 2017 version was just a basic transfer from a VHS (or Laserdisc ?) to a DVD. So both the image and the sound had some limitations compared to what we should expect from a proper DVD, in fact the mix is the same as your original VHS (so, almost no low frequencies for example).
They first did a remaster of the audio in 2020, to stream the concert on Youtube to support research/hospital against the Covid pandemic. But the source was the stereo master tape. I guess it was only re-equalised and remastered, but it was already a vast improvement.
But this version is a proper remix (same as what Nick Davis did with the Genesis albums in 2007-2009), from the multi-track tapes. So they checked everything : relative volume for each instrument, EQ...
The overall sound is way better, more balanced, every detail is perceivable.
They improved the video too. It's not a proper "restoration", because there is no "real film", only a VHS source. They tried to improve the image with some algorithmic software (similar as what the Genesis Museum did with the Bataclan Concert). Honestly, it looks great. No perfect, but great.
Still, the most important thing is the sound, and they really did an amazing job.
You can watch some extracts on Youtube on the official Prince channel.