Having experience as a HC is not always an indicator that he'll be successful (see Jeff Fisher).
The same can be said of the hot-shot coordinator (see Steve Spagnuolo a few years back)
So I can't say one or the other is THE answer. What I'd want is a coach :

who knows how to lead men
who knows how to get the best out of his players
who doesn't lower performance standards just because they're hard
who has football smarts, is football savvy, and expects his players to have some
who knows how to win
who has great instincts that pay off
who can evaluate and differentiate between talent and potential in both players and staff
who knows how to foster and nurture a healthy TEAM environment
who is a strategic thinker and doer
Who has the respect of his staff and players because of all of the above

Get somebody like that and whether or not he's an experienced HC or a hot-shot coordinator won't matter

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