Bah, they really screwed with the book when they made that movie.
It had its own appeal, but it wasn't what Heinlein would have approved of.
In the book they were actual exoskeletons, much more like Starcraft Marines with jump jets than lightly armored foot soldiers, and definitely not something that fought in groups- in the book, they were elite soldiers who went jumping in on raids to destroy specific enemy installations and infrastructure.
Nice costume, though.