I use this for a literature study. My kids really like Andrew Clements as a writer, and once we use this book, they go on to read a lot of his other books independently. I also use some of them as read alouds.
I have found Frindle to be one of the kids favorite book to use in a lit circle. I have also, and my media specialist continues to, used the book for our schools Battle of the Books. It is a fun easy reader for fourth graders to use. Even if some of your low kids have help reading they will get a kick out of the book. Great choice!!!!
I did Frindle as a read aloud. My 3rd graders LOVED it and we now refer to pens as "frindles."
Whipping Boy was a book club book for two years, with the TOP TOP readers of gifted boys. My girls don't like it, and these boys said it was "OK." I think the language is a barrier with old english terms not used relatively today in the 21st century. They just didn't get into it.