It is very easy for me as an admin user with no coding skills at all - I can set up rules in minutes without having any problems or issues understanding what they are doing! The only downside we have found so far has been how difficult it was initially getting our account setup (we had some issue where there were not enough permissions etc).
We managed eventually though but would recommend contacting their support team if your initial attempts don't work out too well otherwise things may get lost/forgotten about when trying again later down stream! There's nothing specific i dislike really just need more training options available which isn’t always possible due to time constraints within businesses / lack staff resources e tc.