Nokia Lumia 820 or Nokia Lumia 640 Which is the better [ONLY THESE TWO PHONES]?

Due to being messed around with warranty.

I have now ONLY been offered the above two phones which will be BRAND NEW IN THE BOX (no cash no other phone)

Lumia 820 or Lumia 640 here they are side by side
http://www.gsmarena.com/compare.php3?idPhone1=4968&idPhone2=7055

Pleases just select which is the BETTER and briefly why
thanks

Read more: Nokia Lumia 820 or Nokia Lumia 640 Which is the better [ONLY THESE TWO PHONES]?