Since I can't really decide, I came up with the following idea:
Use both programs together. iPhoto will be used for importing all images I shoot with my camera and Aperture will be used for editing and organizing the library. I can always use both, and Time Machine will work for my iPhoto library. The Aperture library won't be that big since it will not contain any images, so I will be able to backup it up daily with Time Machine, using a script to end Aperture and then start it again (I allow a couple of hours for TM to do its job).
That way I keep the best of both worlds!
I don't see the point. If you are going to use iPhoto to keep the image files and Aperture to make adjustments? Why? Aperture is not very god at making adjustments when you compare it with Adobe Elements. Elements is half the price and 100 times more sophisticated about how it can edit images. If you are going to use two proograms choose iPhoto and Adobe Elements.
The ONLy way I'd recommend Aperture to anyone is if they were wiling to drink the whole pot of cool aid, so to speak. Apertures whole point and reson to exist is that is simplifies your workflow. If you don't let it do that it is a wate of time and money.
Here is a good way to decide what to do: Write down the workflow. Then write down another. Look at each and count of the steps see which is easy and does what you need.
I've never even heard once of anyone using a combined iPhoto/Aperture workflow.