The best part about casterar was its ease in using it for creating BPMN diagrams which helped us understand our processes better than any manual diagramming could have done! I would say there isn't anything much we disliked or didn’t like at all as far this goes!! You should try out their demo version first so you can get an idea how your workflow looks before going ahead & investing time into learning them fully.
We used casterra only because my client wanted me too create some flowcharts/diagrams (BAML) but when i realized what they were looking forward towards - having everything mapped up front then why not go full steam :)The benefits are:-.