Quite an important book for the influence it had on other things. The famous Judge Dredd story The Cursed Earth is a direct rip off of the book and you can clearly see the influence on the Mad Max movies.
However, the book feels like a bit of a missed opportunity. The central premise is great: a journey through a radioactive wasteland to deliver supplies of a vaccine. The reason they cannot fly there is a bit of delightful hokum. However the scenes on the road are not as well executed as they might be and there is a bit of a lack of creativity there.
I quite like the post apocalyptic genre. This work is alright, but critically important in tying the idea of a road to the idea of a post apocalyptic world which is critically important in the works of art that followed (for instance "The Road"). In the end a more important work for what it began and the ideas that it first enunciated than as a work of art in itself.
I would say that it is really best for those people who like post-apocalyptic stories, but otherwise, there are better things for those who merely occasionally dabble in the genre.