@Darcar
I have the 8 speed ZF in my BMW F11, its a cracking gearbox almost seamless changes and yes the mpg (in cars) is typically stated to be a bit better than for the manual however that could also be very dependent on ones right foot.
When I was looking to buy van to convert my first choice would have been one of the Ivecos with the 8 speed auto box but at that time they were beyond my budget.
I have a 5000kg Dually Sprinter that has now done 315,000 miles with the 5 speed full Auto box, the gaps between ratios are significant. My vans box can react too slowly, it loses considerable speed before changing down gear with cruise control turned on when tackling hills especially at 30mph. I tend to have to preempt what the box will or rather won't do to maintain a more consistent speed.
Unusually for a full auto It does provide a useful degree of engine braking if used manually plus I also have a Retarder.
The later 7 or most recent 9 speed variants are probably far more refined.
I also have a VW Crafter with the robotised clutch Semi Automatic 6 speed box, this apart from having a very low 1st gear is better at maintaining consistent speed, it also has true engine braking if required. it does hold the gears a bit longer than I like at times so I tend to nudge it up manually occasionally, it behave better with the Cruise control but that could simply be because the Crafter is lighter than the Sprinter and has the extra cog.
I like autos and haven't owned a manual vehicle for years, my last was a Supercharged V8 MG.