I think the problem is the dedication to make WORKING firmware updates, or lack thereof. As time has gone on, it's clear to me DLink has put less and less work (or maybe talent) into firmware updates for this router. I will say the router works WAY better for me with non-N cards than with N cards.
Would I buy again? Tough call, honestly.
I hear the excuse of "this is not a business class router" and that is true. However, I say if you implement a feature in firmware, it should work, PERIOD. If you can't get it to work right, then don't implement it.