I have read and re-read this book series so many times!
I think younger YA reader's are going to be the ones most likely to enjoy this series and If you like any of Meg Cabots other YA books then you probably will like this series!
The best way I can describe this book is Buffy the Vampire Slayer but with ghosts instead of vampires! The main character (Suze) is a tough girl who occasionally resorts to violence when she needs to but at the same time she is also pretty girly.

It's a fun easy read with a bit of romance and a bit of mystery and you could read to book in a day or two if you feel like it.