First, I know that Aisin is an Asian company, but it is an Aisin transmission. Just a friendly jab :). Second, the Aisin does indeed have extra maintenance. The 68RFE needs a fluid change every 60k to 120k miles depending on duty cycle. The Aisin requires fluid changes every 30k, and then fluid + filter every 60k. So there is some increase, and it's difficult to find Aisin ATF fluid. Seems like the dealerships are the only ones that carry the correct fluid at this point so it's a little pricey until the aftermarket picks up.
You can click the truck in my signature to see my lifetime fuel economy at whatever average speed I have noted in the notes. Other added expense is that the fuel filters are very pricey for a modern diesel. Do it your self and you'll save about 200 bucks from what a dealership will charge you. It's about 90 to 120 bucks for a pair of filters (new trucks have 2 filters, 1 on the chassis and 1 on the engine). Loving my truck, had a few teething issues but they're mostly resolved now.