Towing, the Eco is a little better. At high altitude I'm sure the Eco will dust the 5.0 though.
Mileage, about the same between my 5.0 and guy at work's Eco. His is 4x4 crew cab Eco, mine 2wd Ext cab 5.0 with enough tools in the back that it weighs as much or more than his.
We both avg 18-18.5 commuting mostly highway.
The 5.0 tows great. Best engine/trans combo I've ever driven for a gasser. I have yet to pull anything with GM's new 6speed auto/6.2 or teh newest 5.7 Hemi's (6speed now too?).
It pulls better than any of the big 5 (incl Nippon and Yota) of a few years ago. I avg about 13mpg pulling a 8 to 14klb trailer with the 5.0.
'06 X2 MCX
"I understand why some people may not want to do this the way I have recommended but I can't understand the death grip some people have on a toilet plunger with a hose fitting." -JimN