I've done some basic weapon animation in it. You don't need to use bones, just set up your keyframes and move things, basically. Keep track of your frames sections for the FPE. It gets a little more tedious when you're doing multi-part weapons (sliders, clip changes, etc.), but it's still a relatively simple procedure.
I've also done two handed melee animations, but it's a pretty cheap effect because no matter how many weapons you have or how much they move, there is no damage inflicted till the end of the animation. For instance, you can swing two swords around for five minutes if your animation is long enough, but the hurt don't come till it's done.
If you do two handed guns, it's pretty much the same thing. Only the finish of the right sided animation draws blood. At least, that's been my experience.