What are the differences between Valhalla and Flkvangr in Norse mythology?

In Norse mythology, Valhalla is a hall where warriors who die in battle are taken by the god Odin, while Flkvangr is a field ruled by the goddess Freyja where half of the fallen warriors go. Warriors in Valhalla prepare for Ragnarok, the final battle, while those in Flkvangr enjoy a peaceful afterlife.