generally, what i like about the jdoramas, so far...
1. they depict real stories of real lives of real people.
2. the way the dorama portrays the culture and its effect on the people's lives.
3. the moral values and philosophy that embody the stories. so many lessons to learn in connection with our real life. suffice to say, the situations and dialogues are thought-provoking unlike the stories of kdrama(well, there are 2 stories w/c are good for me) and pinoy(napaka-intense ng mga emotions, OA)...basta for me, ah ok, o sige ang end result. jdoramas tend me to contemplate the philosphy behind each story.
4. magaan xa panoorin...kung baga entertaining and yet, it's no waste of time (and electricity) bec of so many things to learn reg the connection of the story to japan's history and culture. of course, other than, as everyone says here, its unpredictability.
5. the smooth flow of the story.
what i don't like
1. actors sometimes tend to act animatedly. u just have to read the storyline first before u watch it so u'd be ready.
2. too short, minsa nakaka-bitin.
3. original copies of blockbusters have no subs. we have 2 or 3 but not really a highly-rated ones for me kasi about martial arts. 
more to come once i have thought of more details.
at the end of the day, to each his own lang naman talaga ang preferences. 