First, realize this particular build was designed for one thing: impressive gaming at 1900x1080 and little else. If your build isn't geared that same way then it's pointless to compare them. So I'll have to assume your suggestions are also intended to compete along those lines.
As someone with a 6870, I think you'd find the graphical muscle a little lacking onyour build compared to this one. While I can max out just about everything at 1680x1050, I'd be a little hesitant to try it at full 1080p ( and I've got a 2600K and 8GB RAM behind mine. ) Yes, your build will get perfectly acceptable results at medium or high detail levels, but you'd be hard pressed to average 40+fps on highest/ultra detail.
I don't think anyone would gainsay your build on overall system horsepower and usage balance, but for pure gaming it may fall a little behind.
And finally, a lot of people simply respond to these things with, "I would have just spent a little more." But if you justify one slight budget increase, then you justify another and where does it stop? I realize that many people go just a little beyond their build budgets ( I did myself last year when my $1200 system suddenly ballooned to $1450. ) However you have to abide by some kind of rules in these SBMs or there's no real point to comparing the systems together. ( Perhaps they could change in the feature to allow a +/- $50 and then penalize scores for going over budget and boosting those that stay under, but that's another point entirely. )