I find it irritating to see a priority grading column that can't be removed or something similar in GTD software. It's like the guy didn't even read the book.
but a lot of those apps don't claim to be a canonical GTD program like Omni Focus does .. and the omni group has resisted a lot of flak from the user base even during the alpha testing to keep priorities out of it . There's work-arounds though if you require priorities ,flagging items is one way , but I use flags for items that require a lot of energy and focus ..I try to do those in the morning or when I'm fresh and filter them out if possible when I'm toast .
Just as long as I look at everything often enough to " feel good about what I'm not doing " .