Hi Mokel!
How exciting! I remember it well . . . the waiting, the anticipation, the fears . . . .
There are lots of differences, and unless you have a compelling reason to sell your PE I would suggest you hold on to it. For one thing, you might decide you "need" both!
The biggest problem I've had with my EE so far is the browser crashes. So far I have tried 3 browsers and they all crash. The biggest plus is the huge e-ink screen and readable web pages on the LCD.
In a way, the EE has made me like my PE even more! For one thing, I no longer ask my PE to do any serious work -- I have the EE for that now. I use the PE for shopping, light gaming, and reading when I'm out and the EE for reading at home and most else. The PE is a great help (side by side and over our LAN) in setting up the EE.
I just got my gelaskin for my EE and it is beautiful!