Aperture is more for organising and basic image enhancement and correction. It is the starting point for your image management. It's ability to handle RAW files is wonderful and it's RAW mode, in my view, is much better than Elements.
Elements is the advanced mode for image manipulation where you can do things with Layers, Dodging and Burning and other specific editing to create special effects for your images. There is no doubt that you can do Aperture type things in Elements but it is much better done in Aperture. Aperture, however, cannot do the special effects that Elements can do.
The ideal solution is both.