Eagles are more expensive, due to their demand. I know the higher premiums add a lot to the dollar-cost average of acquisition, but that is simply an intangible added value, that is recouped when the coin is sold.
I consider that part of the premium I pay is offset by the fact that I would be able to liquidate the Eagles for cash in an instant, if I needed to, because of their popularity and easy negotiability.
I am sure the same would be true for the coins produced in other countries.
Not only is the Eagle popular, but this is a great time to be buying. With the Dollar being strong, and Silver being weak, a Gold-Silver Ratio of 75, and the free-shipping offers, the decision to make a large purchase seems like a no-brainer.
I just received a new credit card, which offers a very generous credit line, and no interest payments for eighteen months. I am considering getting a Monster Box with the card, as I feel certain that the price will rise before the card has to be paid off to avoid paying interest.