Are they all created equal: Short answer: NO
Long answer.. I am not qualified to give specifics (Have not done the research)
But: Some compaines make drives optimized for different use, I think it's Western that makes one optimized for video storage for example, and others for data other than video.
Some are faster to store and/or retrieve data
Some companies have better reputations.
I bought my last half Terabyte drive for 250 bucks at Staples last December.. It came with a Toshiba Sattlite C-55d wrapped around it and Windows 8.1 already installed. Best price on a 500 Gig drive I have found.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times