I've had great luck with factory recertified seagate drives from ServerPartDeals, i wouldn't touch a seller refurbished drive with a 10 foot pole though, they are very different things.
"Refurbished" has lost pretty much all meaning these days. It could just mean they wiped off some grime, it could mean they fixed a board fault. You can't know. I've had ebay sellers pass off used things as refurbed just because "it could have been refurbed at some point" which is just lunacy. Stay away from refurb kit in general unless you don't have a choice in my opinion.
Not to mention the SMR fiasco, as well as their deceptive marketing around the RPM their drives run at. 5400 RPM "class" isn't 5400 rpm, it's likely a binned 7200 drive.