I understand your question. I had the same one, pretty much. I browsed the forums a while, took a look at the official sites, and decided to download DKS so I could have the "big deal." Getting DKS is like getting two games for one, as there's not much of a price difference. From what I've seen of the FoV of DKS, it's looking really good!
Just be forewarned that some people are having problems with "steam" downloads. I have read many threads of people having problems with that 'place', and that is part of why I decided to download my digital copy directly from Larian Store. I had checked Amazon, and a couple of other places listed by official Larian sites (I don't recall which one), but figured it would be best to just stay closest to the source (hehehehehe... did you get the pun?).
I hope this information helps you.
Also, I believe Trippy mentioned (as well as answered one of my questions that I posted within a couple hours ago) that if you get DKS, it will NOT be compatible with your disc Ego Draconis. I have regretfully had to let go of my awesome characters from ED, because I purchased DKS-- at the time I didn't know I wouldn't be able to keep previous characters. So, if you get DKS, you can start from the beginning, or start a new FoV character (which is what I did just because I wanted to see the new game). I am thinking, now that I know I can't use my previous ED characters, that I'll go back to the beginning w/ a DKS character, and see what kind of improvements were made. There was a lot of input given in the forums during the development of FoV, and the Larian folk kept a close eye on what was being said. Since they did that for me (okay, fine, "us"), I suppose I could go to the "trouble" of creating a new character from the beginning to play from start to finish
I need more hours in a day! :p
All best, and I hope my information helps you.