Wanted to try out the action after I recently bought it. Sought a difficult exposure, camera on a tripod and bracketed three shots.
38 is the middle reference exposure.
39 is one stop overexposed.
40 is one stop underexposed.
3940DRI is a combination of 39 and 40 with the DRI action applied.

The 38 middle reference exposure seems ok, but note the blown out sky with loss of detail in the tree and the overal darkish house elements and front trees.
39 has a nice exposure on the house, but the sky is completely blown out. Alle edge detail aroun the house and trees is lost.
40 has a nice 'dramatic' sky, but the other parts are clearly underexposed.

3940DRI came out great, be sure to compare it to 38! The dynamic range has been significantly improved. Good edge detail, great sky, nice front exposure and detail. The detail of the treebranches at the right is all there and not lost. Overal a much more pleasing image.
This photoshop action works great for me, I have already applied it to some difficult low light subjects with 10 seconds exposures as well.
A good investment, because I already made some money because of it. :)

No other post-processing but USM is applied. So no levels, no curves, no messing with colors and tones.