Using the right tool for the job

We’ve been having a discussion internally among the Notes developers about how to best write hide-when formulas based on user roles.  There was a group who usually used @contains, but we have run into problems where the substring is Null, because then @contains always returns True.  I’ve always advocated using @ismember because it seems to be a more accurate function when I want to know whether or not a person is enrolled in a particular roll.

My supervisor, who is a brilliant coder, prefers to write hide-when formulas in this way:  write a formula for who should see the item, then make it a negative using the ! operator (and changing booleans as necessary).  I’ve always found this a bit difficult because my mind doesn’t work this way.  Also, I chafe at things like !@ismember when there is a function called @isnotmember.  I feel certain that the latter must be faster (albeit fractionally), and I find it easier to read.  I guess it’s just my feeling that we should try to use the tools given to us that are best suited for the task.