I am trying to learn about FP-LAPW software. I would like to know how well FP-LAPW outperforms Pseudopotential PW calculations. What are some properties/calculations/quantities in which FP-LAPW gives consistently better results than Pseudopotential PW theory? I know that FP-LAPW should give better results on almost everything (after all, it is an all-electron calculation). I am specifically looking for calculations where FP-LAPW gives much better results than Pseudopotential PW.
In all cases FP-LAPW will be better than Pseudopotential + Plane Waves calculations. However, FP-LAPW calculations are better at calculating properties which involve core electrons (e.g. core level shifts, hyperfine structures). Such calculations are often not possible with Pseudopotentials + Plane Waves, or are more complicated.This is because PP+ PW calculations do not treat core electrons explicitly. Furthermore, FP-LAPW calculations do not depend on pseupotentials. Although one can test pseudopotentials to check for transferability, there is no guarantee that the pseudopotential works for the system that you are simulating. As a result, "artifacts" due to pseudopotentials can be avoided with FP LAPW.