unless your bench marking, my rule of thumb for a games machine is get as much as you want for the price you want to pay, we normal buy more than we will ever need for gaming and faster than we really need, most here like as much speed as they can so will say faster is always better, but for every day use im sure most couldn't tell what speed ram was in there pc, i've been doing this for years and only benchmark when i fit new stuff against an old kit, and as stuff moves on the rules change anyway.
i'd spend the extra money on something else, for gaming now days a good vga makes more sense than the fastest ram out there with a half decent cpu, but then again i could be wrong and maybe told so, it won't be the first time, or the last.
8gb of any will be fine for me, i've had branded and unbranded, as long as it's cool and stable and works with no errors im happy.
to spend over the odd's on something that may or may not get you 1 more fps in a game is a waste, the next up cpu or a driver for you card updated would give you more