I would like to get some book recommendations. Are there any services that you can suggest?
What Should I Read Next is a decent service. It doesn't require an account, which is an added bonus. You simply type in a title or author and the service will recommend books by the author or similar to the title you entered. The links provided will point you to Amazon for further information, so it is not ebook specific (and may take a few manual steps to find it on ibooks).
There is also this post that lists the top 10 book recommendation platforms (though it is a year old and includes the Sony Reader Store which no longer exists).
You may give a try to some book specific social network like Goodreads; you don't need to register to view its contents, so if you look at a book page you can see that it shows many sections like "other books from the author", "readers also enjoyed", "lists with this book" and so on.
Of course if you choose to register you will have more options, like rating books you read to get more personalized reccomendations, following people with common tastes, and all this kind of social media stuff.
Try the book recommendation tool on Zolabooks.com/recommendations. You enter a title, it recommends four others. If you click on one of the recommended books, it re-enters the search using that book as the seed. The service was built from the foundations of Bookish, a company that was founded by several of the large publishers.