I asked the same question on a 6.2 ford Facebook group that I'm in. The nutswingers were almost as bad as the hemi forum. Reasons to not get a 6.4:
1. Ram's break all the time.
2. Ford'superduty hold their value twice as well.
3. The 6.2l is a beast.
4. The 6.2l can pull 25k lbs on a flat surface.
I cannot make this stuff up.
i have my ram 1500 crew cab with the hemi 5.7 for 5 years now.bought brand new.50,000 miles and no problems with the truck at all.had one issue with a 150 part covered by warranty.i tow my 3600 pound mustang on my 1700 pound trailer with no issues.gets decent gas mileage towing.plenty of room inside.i have the 5.7 box.just replaced my first set of tires and brakes.other than regular oil changes very low cost maintenance.