What's the difference between a MetalPak and a SteelBook again?
MetalPak is manufactured by Star MetalPak
SteelBook is manufactured by Scanavo
Main big difference is in the spine.
I've included pics for comparison of the spine as well as exterior and interior of metalpak vs. steelbook:
MetalPak spine - exterior
SteelBook spine - exterior
MetalPak - interior
SteelBook - interior
Most collectors prefer the SteelBook to the MetalPak because it is sturdier and has a much more classy look.