Apologies for digging up an old thread, but I have to share this.
The attached image shows the difference that software can make to the final processed image. On the left is the image I posted previously of the Horsehead and Flame Nebula region, processed with DSS and Darktable (a linux equivalent of Adobe Lightroom). On the right is the same set of lights, darks, flats and dark flats processed with a trial version of PixInsight.
Keep in mind that these are 4min subs with a DSLR on a hot summers evening with ambient temps of 23-25 C
Now I'm still learning how to use PixInsight... but IMHO - night and day