I love the 5.9 even though I'll end up with the bigger Cummins because I want a pusher. But I'll still get a 5.9 if the deal is right.
I work on a boat and our generators are 5.9 6BT engines. We put 60-70 thousand hours on them before they do a top end on them. And we run them usually 72 hours straight before swapping to the other one.