I use both. Many of the stories I write have a Storyform that is either uncommon or has not yet been written. (With the fact that I can barely find movies that I enjoy, and there are over 32,000 Storyforms, it’s no wonder that I write the odd ones out.) Thus, I need the Dramatica program to actually figure out how the model gets twisted. In other words, there are no stories analyzed in Subtext that match the Storyforms that I have.
From here, I use Subtext to work out the feel of more difficult parts of my story. By using Subtext, I can load up the reports from Dramatica, and get a basic outline. I modify that outline with the tools in Subtext, using gists and re-arranging story beats to better match my idea. Since Jim’s service divides up a story into a structurally appropriate outline, it can also ensure that you don’t move things in a way that would break that structure. Once I’ve finished with that, I may or may not move to a more free-form program, depending on the story I’m writing.
The treatment that you can get from Subtext can be very useful, and for some stories, I’ll actually use that. For others, I’ll need a deeper outline than the treatment provided by Subtext, but it makes for a good starting point in those cases. Thus, there is use in both.
Also, I totally agree with @lakis. I think we are, in effect, saying the same thing from different points of view and experience.