Complex sentence: E-book readers are similar in form to a tablet computer, and usually refer to readers that use electronic paper, which means better readability of their screens especially in bright sunlight, and longer battery life.
Split into simpler sentences: E-book readers are similar in form to a tablet computer, and usually refer to readers that use "electronic paper". The main advantages of e-book readers are better readability of their screens especially in bright sunlight and longer battery life.