Welcome to the forum.
This article is a bit older now, with changes to both PrPro CS 6 and PrE 11, but most aspects still hold. PrPro CS 6 has added even more "differences" though: http://forums.techsoup.org/cs/community/b/tsblog/archive/2011/10/18/premiere-elements-9-vs -premiere-pro-cs5.aspx
About $700 dollars is also another difference
BUT... you will need to buy CS6 if you want to pay once and have a "perpetual" license
Anything after CS6 is only via the Cloud, where you pay a monthly fee to keep the software active
As far as I know, Premiere Elements is NOT on the Cloud, so you pay once