Great addition for Aperture users....layers! Don't let the name fool you. There's a layers component to Perfect Effects 4 too. Just installed it and it has both an Effects and a Layers plugin.

Wish I could dig in further right now. Looks like a lot more free effects than the prior free release. Thank you OnOne!

http://www.ononesoftware.com/products/perfect-effects-free/

UPDATE: Got a few minutes to play around with Perfect Effect 4. Much smoother interface and loads of effects for a free product. Here's a before/after example - this is literally 4 to 5 minutes maximum of playing around (and most of that was exploring the various effects).