He 's young and promising, solid season with Lyon (they have to thanks him), but IMO he did only 1 good season. At the same age, Mamadou Sakho was a regular starter at Paris, capitan of the team with 3 or 4 years of solid performances...
I have not a definitive opinion on him, it's just funny to note that in this modern football, only 1 good year can transform a player in a young star.
Apart from his injuries, Benatia is a top CB. Not realy suited to Bayern's stupid high def line though, he's more the type of defender Atletico would field.