I hate automatic features

(Though I'll confess to using Optimize to help make LODs occasionally). In all seriousness though, I never find them to be much help unless I'm creating messy models in the first place.
EDIT: Ok, first and foremost: the greebling on the guns has to go. I know it looks nice from
really close up, but you're using about 10x or more the number of polys that you need in that region. That level of detail will never show up in-game. You've also still got a lot of very small polygons that are either near-planer with those around them or are breaking up edges unnecessarily; I didn't go over the whole thing with a microscope (and .3ds is too crappy a format for that anyway) but I noticed a lot of wasted polys around the cockpit area and the missile tubes, specifically where you've got indentations that almost go all the way across a surface but not quite, and you've got extra vertices hanging around. These faces are really small - they won't get a single pixel in-game - but they are butchering your polycount. There are some other optimizations, but Galemp can probably point them out better than I can.