I just got my single drive in the mail from techyparts. I ordered a "B grade" drive but didn't notice any scratches or anything.
SMART data showed over 35,000 hours runtime (over 4 years). only 19 power on cycles. About 24TB written and 7.5PB read. Also a single short SMART test presumably run by the seller at 35,000. No defects. Currently running badblocks which will take forever and I will report if it turns up problems.