Paratroopers aren't much use in HoI2. Too much research required to even get them started, especially if you use a mod with a realistic techtree.
For the USA, it's two infantry techs. (And I'm playing Armageddon, not vanilla HoI2, so paratroopers are better.)
And they're just plain more fun. Especially when I have 550 IC just sitting there. (Declared a phony war on Tibet at the start of the game to get full industrial capacity and built a mess of extra factories.)