Hi Tom,
We are always looking at hardware and balancing the price increase versus actual benefit. The Retina screens are pretty impressive for clarity, but they are still behind in terms of brightness. The new Retina screens offer about 410-420 nits of brightness... baseline sunlight readability starts at about 450 nits. The iFly 720 and 520 have a effective nit value of about 650 nits. While they are not a crisp, they hand the sun much better.
In a bright sunlight, iFly 720 users report much better sunlight readability than the iPad. With that said the screen resolution or sharpness of the iPad is definitely clearer. However in a bright cockpit, I think brightness weighs in more important than sharpness. We sharpen and enhance the sectionals to address this too. Though, that sharpness is more noticeable on the iPad / Androids.
With that said, we will continue to develop and seek out new hardware improvements to bring to the table. We are currently pretty happy with the 720 and 520 performance, but will continue to be forward looking. Thanks for checking in with us and for your feedback.