Marantz or Onkyo with Martin Logan Aerius+ bi amp?


I have just bought a pair of Martin Logan Aerius and I am looking to buy either a Marantz sr 6003 receiver, 8 ohms, 7x100 watt per channel or a Onkyo tx sr 876, 4-8 ohms, 7x140 watt per channel, to drive them.
Both of the receiver are use but in very good shape.
I have 2 questions:
1- wich receiver can provide the best sound and best video Switching?
2- both receivers provide bi amping capacity, would it be too much power to bi amp the 4 ohms Aerius?
jf