Just last year I helped draft SAS code guidelines for my division, and this debate of course came up. From experience, I find mnemonic comparison operators hard to read. A lot of our code is from mainframe days, so the variable names are short. This makes them hard to distinguish at a glance from the mnemonic operators.

So our guidelines sIt might have helped that nobody older than 30 volunteered to be part of the guideline group, but we decided on using symbols unless.

Now I partially ignore my own rules, like Pragmatic Priya, especially since I moved to programming in Enterprise Guide. EG has syntax highlighting for AND, OR, and NOT, and I never liked used ^ for NOT (too hard to notice). However, I still cringe and hit CTRL-H whenever I see mnemonic comparison operators.