Well I caved into my nostalgia and bought Iron Storm.
I'm not disappointed, its pretty much how I remember it, but it shows its age and is not as spectacular as it once was.
All in all if you want a decent challenge and a FPS with a slightly unique setting, then you could do worse, but don't expect anything mind blowing here.
I'm spending my afternoon enjoying it, you could too or just buy Duke Nukem which holds up a bit better.