The DVDBeaver review shows the difference between MGM and Criterion, and you can easily tell from the screen grabs that there is a notable difference between the two. Kino's 4K is hard to tell any difference from Criterion's, it looks identical.
Steve McQueen is the star of the film so it would only make sense to feature him on the cover. The original poster is good, but there's too much going on, it looks like It's A Mad, Mad, Mad, Mad World.