There’s a new player on the links tool market - Serpi.co.
Using Majestic SEO‘s data, they allow you to view link data of up to ten competitors at once, let you track keyword rankings over time, set up automatic alerts, and provide you with historic data that goes back to 2007. They also offer a link building submission service which is not a part of this review. They offer a guided setup and have several tutorials on how to best use the system, and they have a blog.