It's very different, a lot of the book is essentially explaining Heinlein's personal philosophy/making a case for how the military has the potential to shape you and society like nothing else. The rest is talking about the particulars of power suits and their management and pretty girls in skirts. The bugs almost don't even feature.
The book is also very pro-war (in the sense that the author believes that only veterans should be allowed to vote), which is ironic as Heinlein spend WW2 working in a naval dockyard (with Isaac Asimov and L Sprague deCamp) and never saw a shot fired in anger. It's hard to see how a serious film of the idea (if not the book directly) can be anything other than a right-wing fantasy.