Hi,
I have a couple 647's here and they work quite nicely with my DIR-655.... I think the price on the current offering is way high because even at that price, it is still about HALF the price of the microsoft .11N wireless adapter....
I just ordered one of the 4-Port versions (TEW-640MB) and am hopeful it will be as stable as the 647's I have.... and as of last night it was only $29.99 with free shipping at Newegg.