After having the opportunity to play both Hunt for Gollum and Conflict at the Carrock several times, I am certain that I vastly prefer them over any of the scenarios in the Core set. Not only are they mechanically more interesting, but they overcome some of the major flaws of the core scenarios. They do a better job of scaling to a variable number of players and do a better job of presenting a challenge over the whole of a scenario (instead of just at the beginning).
I’ve gotten to the point that, when I introduce the game to new players, I do a quick run through Mirkwood to teach them core mechanics, and never let them see a core scenario again. How do other people feel about the difference in scenarios? Do you still find yourself playing them? Is there a danger that the game will lose players who are turned off by the initial scenarios (though, what we know about sales seems to suggest otherwise)?