DDR2's reputation has always been plagued by high latencies in exchange for high bandwidth. When DDR2 was first announced, the latencies were rated 4-4-4-12 at speeds of 266MHz. That is just terrible.
I remember the first time I laid my eyes on PDP's Patriot line of memory. It was during one of my weekly trips to Fry's. The first thought that came to mind was "that's so ugly".