i had it in my 08 6.4l for 3 months . onj the milage tune the mpg went up but only slightly. mabey 2mpg, but if you use the extreme setting as i found out in my case it clogs the dpf very quickly which then causes it to go into regen mode way more (which scales back any mpg increase a whole bunch) then in my case it became so pluged thati could only get 250miles per tank, then te dealer would not warranty the DPF so i went with spartan 274 tunes and DPF delete. I wish i would have done it from the start, the truck run 900% better now than it ever did. and i went from stock (before the edge) 16-16.5 mpg at 70mph on a long trip to 23.5 on the same trip, speed everything with the spartan. oh and did i mention it RUNS 900% better.
IMO go with the spartan or atleast the SCT and delete the DPF and regen function.
If you dont , dont say we didnt warn you