To be honest 16GB is overkill unless you have applications that specifically are RAM intensive like large photo editing, video editing, running VM machines, or working with extremely large files or volumes of files. For gaming 8Gb is plenty.
As far as 4x4 it could be that they had 2x4 and upgraded with another 2x4 or that 4x4 was just significantly cheaper at the time. There was a time that a 4GB stick was much less than an 8GB stick. As of lately it isn't a big difference so I'd go with the higher density of 2x8GB if you do go with 16GB.
I am a fan of Corsair and G.SKill. Patriot is good to, but is sort of in that 2nd tier of my preference. But to each their own. There are only about 3 RAM chip manufacturers anyways so they all buy from them in the end.