I think that the standard aluminum heatsink (link) is a better value than the extended copper heatsink (link). I'll argue that cooler temps can be achieved with the aluminum heatsink by improving the thermal interfaces between the diode/heatsink and the heatsink/host than with the copper heatsink alone.
Sure, the copper heatsink has a little better thermal conductivity than aluminum, but not by much. The extended length of the copper heatsink contains a little more mass, but his extra amount will quickly fill with heat and not add much benefit.
The best gains will be had by removing the most heat from the diode. This means moving the most heat from the diode to the heatsink and then to the host. The copper simply doesn't compare a whole lot better than aluminum here. The copper does a little bit better, but most folks can benefit substantially just by adding some thermal interface material like thermal paste.
In other words, if you have a copper heatsink instead of an aluminum one, it will get hotter, faster, but it won't move heat out of the host faster.
Sure, the copper heatsink has a little better thermal conductivity than aluminum, but not by much. The extended length of the copper heatsink contains a little more mass, but his extra amount will quickly fill with heat and not add much benefit.
The best gains will be had by removing the most heat from the diode. This means moving the most heat from the diode to the heatsink and then to the host. The copper simply doesn't compare a whole lot better than aluminum here. The copper does a little bit better, but most folks can benefit substantially just by adding some thermal interface material like thermal paste.
In other words, if you have a copper heatsink instead of an aluminum one, it will get hotter, faster, but it won't move heat out of the host faster.