2d is about as simple as it gets, nothing new to learn just good tech. The settings will need to be tweaked a little for optimum performance but if you have owned a sonar before it adjusts the same, sensitivity up down till it looks right. The computer really only comes into play if you want to view and play with your maps, which assumes that you want to generate your own maps with the autochart feature at all. That is what made me buy a new unit and I personally love it, no maps for many lakes i fish and i have learned so much about the lake after rendering my own chart it isnt funny.
I would seriously think about getting a DI unit though. So often you cant tell the difference between a big blowdown or stump complex with or without fish on 2d if they are tucked up into it. DI really makes it easy to see fish and tell their size.
The update thing people blow out of proportion. You download a file, put it on an sd card, and pop it in your unit. There are a few possible snags along the way but only if you dont follow the explicit written instructions.