I have not. However I am rather new to the whole DSLR scene and havent realy even started with night shots yet...
Absolutely NO help to you what-so-ever.
Looking at the weblink it looks rather interesting. My only thoughts on "it vs bulb-mode with a very long exposure" would be that in following some of the star trails, on the example image provided in the link, the white trails are not a consistant color/whiteness and some seem to have breaks. I would imagine a long exposure would be more even.
But being a free/donation program makes it easier to get it now and try it out to see if it suits your needs.
***Added edit: Missed it the 1st time. The option to turn all your photos into a timelapse video is a pretty cool little option.