Exposure from Alien Skin is one of the oldest film simulation plug-ins for digital photography around. For years it only worked in Photoshop, and then they added Lightroom compatibility, but Aperture support was conspicuously absent. Finally, with the latest version, Exposure now works with Aperture. Sort of. Exposure itself now works as a stand alone application, and they have changed the interface significantly from previous versions, and clearly they are going for a Lighroom feel. It comes up as an edit plug-in in Aperture, but this just launches a helper application which then launches the stand alone app. There's not much practical difference in the long run, but the App's interface is not retina compatible, and it looks awful on a MacBook Pro. Still, at least they have finally added some Aperture support.
I've used previous versions in the past, and I've liked it, but lately VScO's presets have been good enough for me for when I need my faux film kick. Still, as the grand daddy of them all, Exposure has a lot to like about it, including velvia simulation (although I'm not sure how accurate this is), and things like textures such as scratched film, and light leaks. It's just a shame it doesn't have retina display support.
You can get a 15 day trial if you want to try it out.