All pretty similar performance wise -- even though the GM has less power, the 4.10s it was equipped with (vs the 3.73s in the Ford and Ram) seems to have made up for it to some degree.
I will say this though, not a stinker in the bunch. I'd own any of them. That Chevy 6.0L sounds sweet at the tailpipe, and at full song.
Prev: 2010 Cougar 322QBS (junk)
02 Dodge 2500 4x4 5.9L CTD 3.55
07 Dodge 3500 4x4 SRW Mega 5.9L CTD 3.73
14 Ram 2500 4x4 Crew 6.4L Hemi 4.10
06 Chevy 1500 4x4 E-Cab 3.73 5.3L
07 Dodge 1500 5.7L Hemi 3.55 / 2010 Jayco 17z
All above are sold, no longer own an RV