Since version 9, Elements
has had
Content-Aware technology, and free Channels Actions can easily be downloaded and added. It also has Warp (called the Liquifier) and many other things. The other things Pistola mentions are - as stated - missing.
However, I'd have to agree - the single biggest failing of PSE is that the Adobe Camera Raw that it uses has only about a quarter of the capabilities of the ACR in CS. If you're serious about your photography it's very disappointing to find this, though you may find that your camera manufacturer bundles its own version of Raw conversion software, which may do all that the ACR in CS can do. If Raw conversion isn't important to you, you definitely don't need more than Elements. (But Lightroom has the 'full' ACR, as used in CS and - if you don't want to know about creative editng, compositing etc, is enough for most people).
All in all, Elements (unless bought from Adobe) is less than 20% of the price of CS - it's a good deal....... but Adobe want you to buy CS - so Elements has just enough to give a good result but not quite enough for the professional or serious amateur. It's their marketing ploy to get you hooked.