If you are looking for anime having fantasy, action, thriller with a tinge of romance, then Future Diary won't disappoint you.
Unlike other animes, Mirai Nikki has very interesting female lead. Initially, I felt Yukiteru is MC, but as the series progressed I realized that Yuno(love interest of Yukiteru) has much more depth to her character. I would go as far to say that she is the actual main character.
The one thing that I always find missing in such animes is they don't show life after all the hardships of MCs. Yuno and Yukiteru reunites that's lovely, but please show us what happens after that, show some moments of their happy life.....
Lastly,
The 27th episode was released way after the series ended but do watch the 27th episode name *The Redial* otherwise you will miss on the happy ending.
And do watch the post credit scenes of last 2-3 episodes.