(3) Base Camp
If you haven't read Divergent you can bump Four up to a 4. There is very little context given in these stories, so you might not understand the difference between Abnegation and Candor (or even what these words mean) if you haven't already experienced the story through Tris's eyes.
But Four, narrated by Four, uses an almost identical narrative style and voice to Divergent. We may be getting Four's perspective here, but sometimes it's hard to tell since his voice sounds exactly the same as Tris's. Not that we're complaining. We love Shailene Woodley's voice.