Sword of Shannara has a well-deserved reputation for being a near-total imitation of Tolkein’s Lord of the Rings, with only the serial numbers filed off to aid the deception. It’s not even told particularly well. Readers are advised to skip it.
The Elfstones of Shannara is, in my opinion, the best of the Shannara books. Terry Brooks has exorcised the need to imitate Tolkein, and is now free to explore a somewhat different – and more original – story. While he does not succeed in creating a classic that will ring down through the ages, he does manage a reasonably enjoyable fantasy novel.
Unfortunately, reasonably enjoyable is still pretty flawed. The main issue in the story is whether the main character can access and use the power of the Elfstones. The answer is generally no, or at least not yet; eventually the threat grows to the point where their power can be accessed to smash the opposition and the quest continues. Once the reader has figured out the pattern, there’s not really much sense of threat. The quest is pretty much a standard “take the McGuffin to Mount Doom”, conveniently handed out by a Druid with very little backstory.