The statistics point out to the fact that the chance is really similar:
Source
But considering the question is it worth to use it: why not? It's definitely nice to get some extra potions. Plus, an extra benefit of using the Demonic Blood is the achievement: Demonic Barkeeper! You will get it after using the blood 250 times. (worth 3 points)
When not to use it:
-don't use it when you want to keep some of the Demonic Blood for the Hot Cuisine Event and want to have some spare for Demonic Candy Balls
-when the price on your home-server market is way higher.