They look good to me: four x16 slots spaced correctly to fit in a std eight-bay ATX mid-tower case.

And to citronick's point below.... yes, you sure have to piss around and waste time and mental energy to get that 5th and 6th card to work.  I'm stopping at 5 with the 990FX-UD7 board (AMD) I picked up on ebay (cheap... board, cpu for $100 shipped).