I have found this drama really interesting. The way the characters are portrayed is really well done. Here are the pro's and con's of this drama so far:

PROS
The storyline is excellent. When the male lead puts his life on hold to help his best friend's family out, I found was really noble and made the storyline a whole lot more interesting.
I do really like the way the protagonists in the drama evolve throughout the drama. Some things are never what they seem which makes the drama a whole lot more enjoyable. I like that in every episode there is something new to discover.

CONS
Sometimes the clueless nature of the characters is a bit annoying. The female lead only follows her heart only after certain circumstances. The antagonists really get on my nerves.

Overall this drama is terrific so far. I personally am enjoying it. There is no incest in this drama whatsoever. The male lead is the female lead's deceased brother's best friend and has to act as her brother due to the female lead's mother's health problems. They don't have any blood relation. I would definitely recommend this drama. I hope that this review was helpful. If there are any major spoilers by any chance I apologize, although I tried really hard for there not to be.