I've been buying them at bestbuy and newegg and shucking them from USB enclosures, they're extremely cheap at $169.00 for 8tb and $119 for 5tb. It doesn't matter which version you buy, all 3.5" have the same drives but some come with a usb hub or a shiny case...
Also, if you're careful, you can disassemble them with no evidence and return them under the 2 year warranty. There were zero questions asked, just issued an RMA. One of them was actually just hooked up to my LG (Ubuntu Remix) NAS as a backup drive via usb and died silently. Process and results were the same for all of them. Turnaround was about a month, but of course, I'd already bought replacements and now have spares.
So, regardless, they're an excellent deal. It's basically how my pool grew from 6 to 15 drives in a year.
The WD easystores are $160 right now and aren't shingle drives so I don't see much reason to look at the seagate archives at the moment.
Also, they cannot reject your warranty because you shucked a drive. You might have to take it up the chain a little (and that might make it not worth your time) but US law is pretty clear that shucking an external case does not void the warranty.