There's a nice little single page article in the current gamesTM mag, covering the different Saturn machines available.
Just in case you wanted to start expanding the hardware further
Black (UK)
Grey (orig Jap)
White (revised Jap)
Derby Stallion (translucent blue special ed)
Hi-Saturn (Hitachi model, with MPEG decoder for VCDs)
Samsung Saturn (Samsung ver of above, with particularly low build quality)
Hotel Saturn (7 cd changer, coin operated, completely peripheral compatible, expensive!)
Hi-Saturn Navi (with attached screen, compatible with GPS devices, TV input, karaoke discs..., VERY expensive!)
...though that's likely not a complete selection.