Riflemen have a target size of .97 while Ranger have .8 and they also regenerate health outside of combat at veterancy two.
Other than that I think they're a total bullshit unit. All they do is throw a standard grenade and get Thompsons... Wow Relic, you really went deep in the think tank coming up with this P2W commander
They are totally generic and uninspired and their unit description labels them as "marksmanship experts" while they spawn with M1 Carbines and can get Thompsons.
I would say Paratroopers are strictly better, but they have a target size of one which can be rough.