If you ask me why I prefer the original artist, I would say because I can see they put more effort into rendering the final CG (adding shading, details, cleaning lines, etc...) . And the way they draw Lillian's facial expressions gave her the vibe of an innocent, cheerful, somewhat strong-willed girl, which will make her slow corrution hit hard. I don't get that vibe with the new artist's artstyle.
As for the lastest CG I think it's a downgrade because the new artist had to rush the CG for the demo release. I believe that if they weren't under time constraints, they can released quality CG.
I'll still support this game because i like the developer, they seem to be very passionate about their work, and they listen to feedback.