Having put the unit to the test on a Core2Duo 2Ghz laptop running Rosetta@home for 100% CPU utilisation the results are as follows:
Core 1 56c
Core 2 58c
After 1 hour at full speed:
Core 1 54c
Core 2 56c
The temperatures took about quarter of an hour to fall with the thermal mass of the alloy laptop case then stabilised out, during this time the ambient temperature remained constant.
So a 2-3c across the hot components, on a system that's marginal on cooling it may help out more but I had hoped to get a bigger drop in temperatures especially for the components not covered by the laptop's built in fan.
Finally noise levels are very similar to those of the internal fan so there are unfortunately no benefits to using this in place of the laptop fan for those simply after a quieter work place.