I have an issue with nintex forms. I've made a Nintex form for a new calendar entry. The form has a rule to calculate the End Time. It's just dateAddMinutes(StartDate, 30).
This works fine if you start the form from a specific time within the weekly calendar view. But if you change the time within the form it wont be used by the rule for calculating the new End Time.
I also tried using a workflow for this, but the problem was, that the worklfow needed some seconds to make the new entry, so the user experience was really bad, because they would have to update the page after a few seconds to see their new entry.
So Forms seems to be the best solution if there is a possibility to calculate the End time after the form initially opened.