My Opinion : This is Megan Crewe's Debut, and I have to say I was pretty impressed by the quality of her first published work.
This wasn't my first ghost book... but it was one of the firsts (the second, actually) of the genre where the ghosts are appreciated in the book. And it was the first were they were a funny and light subject matter.
My favorite character was Cass; with sarcastic and witty come-backs; I just really liked the character a lot since she was really funny. I though Tim was a little too whiny... especially near the end.
It looks great just besides Sarah Dessen's Just Listen; the cover is gorgeous!