I ran Buc-ee's pump DEF for a little while, then switched to BlueDEF Platinum.
Very roughly, I am getting 900 miles per gallon on the BD Platinum. I think I was getting roughly around 1000 MPG on the generic. This is after running BD Platinum for about 9,000 miles, so far. I got my truck in July and have put about 16,000 on it since then.
My ability to measure exactly is somewhat limited, since I don't have a pump showing volume down to the 1/1000th of a gallon to pump the BD Platinum from. So, I consider the Platinum basically equal to generic stuff, with regard to how much is used.
What I am counting on being true is that the additive package in the Platinum does reduce build-up in the exhaust system, compared to generic DEF. That is why I spend the extra money ($22/jug, delivered free from Walmart).
I guess it would be nice if the DEF tank were bigger, but I can't say I really care that much.
I run my DEF until I get a warning, then I add a jug of BD Platinum (2.5 gallons). That gets me another 2500 miles or so until the next time.
If I am leaving home on a trip that could possibly be longer than my onboard DEF will last, I pour in another jug before I leave, so I've got somewhere between roughly 3000 and 5000 miles of range with my onboard DEF.
If my trip is going to be longer than that, I'll just get DEF at convenient times/places along the way. Done that before, too. It's really not a big deal.
And, as for the comment about "if I'm going to stop and add DEF, I might as well just stop for the night", uhhh.... what are you doing when you add DEF?!?! If I am time-sensitive, I'll start looking for DEF way before I actually NEED it, and find a station that has DEF at the pumps. It adds 5 minutes (?) to my stop to fill up with diesel, to also top up with DEF.
If there are no convenient places to get DEF at the pump, I'll buy a jug (just about anywhere) and pour it in when I stop for fuel. Usually, you can get it at the same place you're filling up with diesel. So, going in and paying for a jug or two does take an extra 5 minutes, plus the 5 minutes or so to actually pour it in.
None of it is a big deal. I don't understand all the fuss.
I keep a supply of plastic disposable gloves in my driver's side RamBox. I put one on every time I fill up. I hate having hands that smell like diesel. Keeping a glove or two on while I pour in DEF is nothing and makes the whole process of adding DEF quick and painless.