Wall of text incoming.
As it's been said, the 3820 is pretty much the all-around better chip, but it's more expensive. Here's some numbers I'm throwing out there:
4x4GB 1600: $130
Comparable motherboard (GA-X79-UP4): $240
2x4GB 1600: $70
Comparable motherboard (CVF-Z): $240
Now, YMMV, but that's pretty much the gist of it. Keep in mind that the CVF-Z is basically the flagship motherboard for AM3+, whereas the UP4 is a midrange motherboard for X79.
In order for us to give you a good recommendation, we need to know your usage preferences, what games you play at what resolution, and your budget. This is my opinion: a ~$150 difference between the two platforms is negligible, you have a upgrade path to IBe when it comes out, and it will scale pretty well with multiple cards. With the number of features that X79 has, especially with boards that have lots of features on them, it may last you a couple generations.
An alternative is to go Haswell in a few months or go with the 3770k or something. The 3770K marginally outperforms the 3820, but you'll have to deal with the heat issues that IB is plagued with. When both are overclocked to their limits (well with an average D14 or H100 or something), performance will be pretty much identical, but IB will most likely run hotter than SBe.
If I only wanted to go with an AMD system, I would get the 8320 instead of the 8350, especially if you're overclocking. They're basically the same chip, but with different clock speeds. Both chips have basically the same overclocking potential, given perfect manufacturing circumstances.
Reasons to go with AM3+/83x0:
You're on a budget
You like AMD
You want cheap multi-threaded performance that's comparable with the 3770k
Good enough performance for today's titles
May be a good processor for next-gen console ports
Reasons to go with x79/3820:
Upgrade path to IBe
You want good per-core performance
Nice high-end motherboards
You have a multi-gpu solution with a multi-monitor setup
You have lots of hard drives (motherboards with 10+ sata ports)
You want more I/O options (something along the lines of the ASRock X79 Champion)
You like Intel
Reasons to go with z77/3x70k
Want an above average gaming rig (one or two cards, 1600/1440p/120Hz monitor)
Don't need the features of X79, and you want more performance than AM3+
Can't wait for haswell, or decided that the performance gains over the 3770k isn't enough to warrant getting it (mainly applies to current owners)
Reasons to go with Haswell:
Want the latest and greatest
You have an old platform, and you want to upgrade to the newest one
There's some more reasons, but those'll do for now. My verdict: If you can afford x79, then go for it.
They're probably playing at high quality to emphasize the processor differences. They're not benching graphics cards here, even if it is a Titan. The other reasons you noted are more dependent on the graphics card than the processor, given that the processor isn't bottlenecking the graphics card. Plus, in this particular review, they're benching Metro, which is pretty intensive on both the CPU and GPU side. They wanted to go with a graphics card that would give the highest framerate in order to emphasize the differences from the processor, and a graphics card that would give the most transparent CPU results, if that makes any sense. If you did the same test with a 660Ti, the differences between the 3770k an the 8350 would be lower, since the average frames would be lower and closer together. It's kinda like comparing 70 vs. 60 fps with Titan and 40 vs 35 frames with a 660Ti. It's just easier to see the differences with a better graphics card, and to an extent, put the losing competitor in a dimmer light, but let's give techspot the benefit of the doubt, shall we? It gets tiring when people start arguing about websites biasing certain products. Here's
the whole review of the article. They do much more than just benching the processor. They're benching like 25 graphics cards all at different settings.