I have some very limited experience with digital negatives. They are convenient, and they work pretty well. Not all transparency media are suitable, however. You have a lot of control, but creating and printing these negatives is a different world from traditional photographic methods. Like photographic methods, there are a lot of variables, but they are somewhat different variables and are controlled in quite different ways. Incidentally, you have to do a complete recalibration of your system whenever you change materials, which is more or less true with photographic methods, too. There was a pretty good article on "photo technique" magazine for May/June 2013.