AMD Radeon R9 270 Review: Replacing The Radeon HD 7800s - The Radeon R9 270: New, Or Renewed?

Now, as you all know, I'm no expert at this shit. But I'm wondering if I should go with the R9 270/R9 270X or the old Radeon HS 7850/60/70? I'm most likely going to buy the R9 270, seeing as it's in the same price neighborhood, but if I upgrade to this, what would I need to change from this build:
https://pc partpicker.com/p/21DKJ to stay up-to-date?

This is @Aborted 's secondary build for anyone wondering.