The antec is a solid case. Im not a big fan of the length of the case though, you need to remove that middle hard drive cage in order to fit a full size graphics card.
The 650 on the other hand has that dual boot switch on the top. Handy for some i suppose, but not me these days. Has better airflow in my opinion over the P183.
So out of the two I'd go the 650.
If it were me for the same money I'd get either a P280 window, Shinobi XL, and load it out with very low rpm fans.