Delirium was a nice start in a series. I really enjoy Lauren Olivers writing and I like how she writes her characters. 
 It was a quick read and the story was interesting. 
 I think it is a very original idea to think about a world where love is "bad" and they actually don't want to fall in love and think about it as a disease. It is very weird to read but highly enjoyable. 
 STILL, the last book is awful. That is why I won't recommend this series.