It's very difficult to have an exclusive artwork and releases for steelbook, the market is so huge now.
It's all down to control of the Studio itself, if the studio say they only want a standard cover art, nobody would have other cover art on their steelbook. LOL
The only different would be "embossed/debossed", extra goodies like booklet or something else.
As for which version to get, it depends on how you look at your steelbook. I myself have gone through the numeral stages, buying every country releases on a single title to getting the cheapest release on the title.
Once your appreciation on the steelbook collection is gone, it doesn't really matter which one you are getting. Right ?