Kindle for iPhone/iPad

I had one of the first versions of the Kindle before I got my iPad.  Once I got the iPad I was trying to figure out what to do with all of my books.  It was really easy to go back and redirect my books to Kindle for the iPad/iPhone.  Now I mainly read all of my book on the iPad.  I still buy physical books because I like to write in them.  I'm the type of  person that I have to write notes in the columns of my books.