Eventhough the schematic is very straightforward the real challenge in design like this is to overcome various error and noise sources. This kind of sensors is very sensitive to external magnetic fields that are entering IC package perpendicular to its package top plane. Such a field will cause huge offset error or even saturate the output. In static condition (like when magnet is nearby) this offset could be compensated, but typically this issue will occur under high load due to dynamic magnetic fields on the PCB caused either by magnetics (inductors, transformers) or nearby high currents. For real life examples check the build log below - Real life issues.