I have to agree with Ray, the Teric has quicklypushed the perdix to back up status, this is one of those cases where the actual piece of equipment exceeds all logic applied to it based on size, I can see it underwater better than the perdix even with the small display setting.The usable screen of the Teric is 2.1 sq inches. 1.44" in diameter. The usable screen of the Perdix is 2.43 sq inches. 1.81" x 1.34". That is 86% of the usable surface area of the Perdix. The contrast is not at all similar. The Teric has a completely black background and the brightness and resolution means it is more highly visible and readable. Critical numbers are in a font almost identical to the Perdix which means they are far more discernible at a glance. There is often a decimal place used on data that isn't available on the Perdix. The compass around the perimeter of the screen face is brilliant and changes the way my brain uses navigation, making it a natural process without need for action. The use of the screen area on the Teric is a huge leap forward from other products I have seen and used. The Teric is currently the most satisfying investment we have made in scuba gear. The gas blending station at home would have to rank as second.
Edit to add
I actually completely overlook how nice the smaller form factor is but it is really nice. It is easier to don and doff gear when you don't have a brick on your wrist. To me the joy of the interface and how easy it is to see the data on the screen are where I experience the joy of using the Teric. The rest is cream on top.