I have a stock 2012 F250 extended cab 4x4 with the 6.2 and 3.73 gears. I bought it brand new in Nov of '12, it currently has just under 80K miles on it.
What would you like to know?
I've never had an engine related issue with mine. I have had 1 high pressure side power steering hose rupture back in 2016 (?) and I did replace the stock shocks and steering stabilizer at about 40K miles. That has been it.
I tow a 12K pound 5th wheel on mostly flat ground (no mountains in North Dakota). We have been to other states and I have been back and forth several times to my native state of AZ. I also tow a 9K pound flatbed car trailer with my Branson on it, when I'm out mowing fields for hire or other off home site tractor work. If I'm running empty and not towing, I average about 12-12.5 mpg over the 10 years I've had it. If I'm towing my 12K 5th wheel, I'm somewhere between 8 and 9 mpg. The flatbed with the tractor on it gets me around 10-11 mpg. Speed and wind resistance plays the biggest part here. A head wind will play havoc with the 6.2 gasser, more so than a diesel. I try to never tow above 70 mph, and mostly prefer to tow at about 65. That's with the 5th wheel, not as much of a mpg hit with the flatbed. The larger cross section of the 5th wheel acts like a sail in the wind.
The biggest tip I could give you is, if you're towing moderately heavy to heavy, always use the "Manual Mode" on the transmission. Never, ever tow it in "standard" or even "Tow/Haul" modes. The psychopath that programmed the shift points for the transmission must have been thinking he was setting shift points for a 4 cyl Datsun. If you leave it in auto (this includes tow/haul) the idiot computer will down shift the transmission if a sparrow flys by and farts on you. It's ridiculous. In "Manual Mode" you can set what gear you drive in, and you can choose when and if to down shift. I can hold a gear 1 and even 2 gears taller in Manual Mode than the computer will run the same pass with the same load. The 6.2 gas engine makes 80% of it's power at 2000 rpms. Unfortunately, the transmission shift points don't reflect that. No idea why, but there it is.
If I had it to do over, I would have purchased a crew cab dually. Either an F350, or if I could get it with a gas engine, an F450. This is mostly for stability of the rear axle when towing the big wind sail of a 5th wheel and getting hit with strong cross winds. It can get squirrelly when the gusts of wind get over 30-40 mph (which it frequently does here) and that wind is hitting you square in the sides.
I have never felt like I didn't have enough power. I know, the diesel kiddies would lose their minds at that, but putting it in "old guy" perspectives, my uncle used to pull a 30' Airstream all over the country with a Dodge dually pickup with a gas 318 and a 2 barrel carb. He never felt like he needed more, and he chastised me back then for buying a Dodge 4x4 with a 440 big block for "wasting gas".