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If you're just going to wipe everything anyway the best way is to do a clean restore with an external drive ... delete your entire drive with disk utility ... and install a fresh copy onto your computer. You can download the latest version from the app store and then use diskmakerx to make a bootable external drive that you can restore from: http://diskmakerx.com/
 
Which would you guys do?
Neither. I've only installed OS X from scratch once on my personal machine. That time (with Mountain Lion) I installed via a bootable drive from the App Store installer, as mentioned above, and restored my data using Time Machine. That's what I would do again if I were to do it.

If I had to choose between your alternatives, I'd do the latter. Just seems redundant to update if you're going to wipe it two seconds later.
The OS is built to be updated continuously not just between incremental updates to the same version, but across whole OS versions. There's nothing at all wrong with doing that.
 
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