I know Manga Studio isn't free, hence why majority of my peers in art school hissed upon seeing it.I never understood why they were like that, it may have to do with a strict adherence to the one true Photoshop. All that rendering, hahaha... thankful I don't do all of that.
However, as a semi-working professional, it's honestly replaced Photoshop for me in terms of creating comics/illustrative work. The only reason why I have Photoshop CC is for business work. Other than that, I do everything on Manga Studio. Great software, and Hannah's got it right, it's basically a fancier SAI. It takes awhile to get used to, but once you figure out the shortcuts and whatnot, it pays for itself honestly.