Most of the tools, like merge contacts are unreliable. Finding duplicates never remembers previous choices. I have many contacts with the same business phone number. Every single time, the app will try to merge them. When you do want to merge contacts, it doesnt always work.
Updating contact photos also barely works, but this seems to be an iOS problem.
The biggest annoyance are birthday reminders. Why in earth does every app engineer think we need these reminders? There is no way to turn it off!
Eryximachus69 about Simpler Pro, v8.1.0