Yeah, brad, you're going to get a LOT more power out of a home-built computer for a LOT cheaper than if you buy a prebuilt.
Take this $400 rig. Graphically, it'll compete with either computer, and it has an SSD, no less.
For $600, you could build yourself an amazing computer, either using AMD's Trinity, which is an exceptionally good CPU that has no noticeable difference from an i5-3570k for half the price, or using a lower end i5.
Personally, I'd go with the Trinity - they're really not as bad compared to Intel as everyone makes them out to be, they just run hotter.
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