Newegg apparently ships all RMA'd stuff back to the manufacturer.
To end up "Open Box" on newegg, it probably has to be tested okay - but their testing may not be thorough, so it could still be defective.
Ex: Some F3's have bad firmware which doesn't work with all boards. A lot of AMD boards in particular. Some drives have performance issues - others just plain don't show up in the BIOS.
If the drive got sent back to Samsung, they tested it on an Intel system and it worked, they'd mark it okay and let newegg sell it Open Box. Now if it had that particular issue, and you buy it and try it on an AMD motherboard, it'll be "DOA".
I generally avoid OpenBox items.