The choice of annotator model for a particular annotator depends on the developer's understanding of the annotation task: if the annotations have sequential dependencies, this suggests the seq model; for non-sequential classifications CM may be effective with small (≤ 5) numbers of classes; spam may be more suitable if there are many classes, as the number of parameters to learn is low.
there is also a trade-off between the expressiveness of the model and the number of parameters that must be learned.