if your running a LGA 2011 board then yes the 4x4 would be better as you will get quad channel. If its LGA 1155 board then it doesnt matter as you will only get dual channel.
For overclocking they both have their issues:
4 sticks are harder to overclock then 2, normaly need more volts when all 4 slots are populated.
4gb sticks are easier to overclock then 8gb sticks.
I normaly go 2x4gb since gaming doesnt really need anything over 8 gb.