Bottom line is this: Don't let concerns over braking on steep hills affect your decision one way or the other, when it comes to gas vs. diesel.
Its been debated many times, the differences between the two. Gasser engines naturally provide braking by virtue of suction created at the top end when closing the throttle valve. Diesels on their own have no engine braking, but adding an exhaust brake that plugs up the exhaust give them that braking. In the end, both do a good job of slowing things down when they need to, but do so in different ways.
Its not really accurate to suggest that diesels offer engine braking and gassers do not, when the reality is the exact opposite - Gassers provide braking naturally without having to add anything, diesels do not, and only get such by adding an exhaust brake that plugs up the exhaust.
Ultimately, though, since both accomplish the same basic thing when it comes to braking...There are much, much more important factors to consider when chosing between the two drivetrains.
