[John Izzo]

Personally, when I work with clients, I don't like the Harris-benedict formula. But I do tend to use the McArdle/Katch formula. Are they both estimates--of course they are. but when I deal with the general population, I like to have a starting point. That starting point begins with a bodyfat % assessment. (guys will use calipers, women will use Omron (if they are uncomfortable).
As Leigh stated, there are adjustments along the way. I usually begin with a food log and then measure up to the calorie need. is it an estimate? yep, but it gives me a shallow light on what adjustments
(+/-), the client needs to make in terms of diet. I think in terms of the general population, the McArdle /Katch is needed, because they are really going in blindly. Although, each formula you come across is not a means to an end.