I image a 500GB SSD (C drive) with default settings and medium (recommended) compression settings. Non incremental.
I use Intelligent sector copy (recommended) which only copies disk sectors used.
Used space: 383GB
Free space: 82GB
So you'd think, SSD... should restore at reasonable speed....
Well, to image the disk takes about 25 minutes.
But RESTORING the image takes about 24 hours!!!!
Any reason why this is?

24 hours is indeed pretty outrageous.  I assume you're performing the restore from Rescue Media?  If you haven't already, can you try building your Rescue Media with WinPE 10?