Beware, though. Some (if not all) of the buffs overwrite veterancy bonuses while the ability is active.
Interesting... is this the case for similar abilities as well? OKW's Luftwaffles' Valiant Assault and Brit Commando's Assault comes to mind. If so it might be closer to a "feature" that prevents it from being too good when used with Vet 3 units.
Either way I think the take home message is that you get the best bang for you buck using it with Vet 1-2 Units. Vet 3 Rifles get +30% Accuracy and Vet 3 Jacksons get -50% Reload and +30% Sight currently so the buffs are mostly a wash assuming they completely cancel out Veterancy buffs.
Though its important to note that the "Combined Arms" Aspect of the ability is still worth mentioning - the extra vision of Infantry + the Extra range of Vehicles gives you a significant advantage in armor engagements if you can utilize the maximum range of your vehicles with your infantry as spotters.