Seems to do the job, if you're into Starship Troopers, in a standard game you get one core class (there are a couple more if you want to mix civilians or navy characters in there) and then most characters go into an advanced class at 5th/6th level to get some differences.
Characters are weaker than D20 Modern, as they only get 1-3 hp/level (fixed number by class) and start at their Constition score on HP.
Has some skill based psionic system as well, but I haven't really looked at that.