Ghost Size is an overpriced creatine product IMO. From what I can see with their marketing, Ghost draws it's audience from the younger crowd that wants to look like their favorite YouTube star, but the ingredients in their products don't line up with pricing at all.
-(-)Epicatechin has been studied to be beneficial for many different reasons that all positively impact strength, health, and overall fitness. My biggest complaint with Ghost is that they do not disclose the % extract for the (-)epi they are using. I'm skeptical.
If it were me I would save my money and use it for something better. If you want to try out a new daily staple supplement, check out Intramax or try a new flavor of E9. The ingredient profile on these products is superior to Size, and the price point is better. I would also check out Massmax XT or Follidrone 2.0 if you're interested in (-)epi. Both of these products have much more to offer than just creatine + (-)epi