I just purchased two new dive computers. An Aqualung i770r and an i550c. I plan to use the i550c as a backup. I currently have an Aeris Elite T3 and Atmos AI. I am awaiting the arrival of the new computers and am questioning if I should have upgraded at all. I bought both the Aeris DCs in 2006. They work fine except for backlights. I know the i550c is the same model as the Atmos AI with the addition of Bluetooth. I was definitely interested in the Bluetooth capability of the very finicky USB cords of the Aeris models. What do you guys think? was it time to upgrade? I know many will ask why the i770r and not the perdix ai. I wanted the two DCs to have the same algorithm and stay with the same brand. I was also able to pick up the i770r new for $300 less than Perdix ai (a major contributor to choice.) Also, all DCs are ai. I have transmitters for both wrist DCs. I wanted to stay ai. So, let the comments begin!