Their "TI DirectCu" cooler is currently one of their best preforming solutions. Hence, the increase in price.
The cheaper one has an extruded aluminum heatsink similar to intels cpu heatsinks. The more expensive one has an aluminun/copper heatsink with direct contact heatpipes. The more expensive model will cool better with less noise and have better overclocking headroom since the heatpipes carry heat away fron the die faster.