Just recently bought the HHA. I LOVE it. Not only is it easier for me to see the lone green vertical pin (I've always found green to be much more visible to me than red or yellow, which is standard on most multi-pin sights & the vertical pin acts almost like a crosshair as opposed to coming in horizontally), I've found that I've become much more accurate at longer yardage than I have ever been.
I will say I haven't used it hunting yet, but am getting pretty good at adjusting the dial very quickly and quietly.
I also agree with several previous posters that if you just set it 25 when hunting, you should be good out to 30, and is really no different than "gapping" a multi pin sight.