UPDATE - While my hard drive still might be the culprit and may need to be changed eventually, I think I've fixed the problem with the error code I was receiving without having to plunk down a hundred bucks on a new drive. Here's what I did:
1) Changed my DNS numbers to Google's.
2) Did the PS4 safe mode "rebuild the database" thing (hold down the power button on your PS4 until you hear a second beep to access Safe Mode)
3) After both those steps failed to resolve my issue, I freed up about 200 gigs of space and reinstalled the last PS4 firmware update through Safe Mode. The space thing is important - if you are coming close to your download limit, the PS4 will stop downloading anything.
That last trick seemed to solve it. Hope this helps anyone else having this problem.
ORIGINAL POST - I upgraded to the 2TB hard drive recommended in the old GB video, but now it's crapping out on me. For those of you who have upgraded within the last year or so, what brand did you go with and how's it working for you?