Since I only fly DL, I have different perspective and method. I search at different times of the day and days of the week to see if I get different, possibly more economical results.
I honestly don't know. I have zero experience with any other fare or flight search technology. (My choice as I'm not technology-disabled) DL works well for me, and I've never had an employer who didn't let me use them. When I want a flight for work or personal use, or an award ticket, I search as early and often as possible. Obviously it doesn't happen that way for work much, as I'm at the mercy of my client's schedule.