Amazon is not unlike eBay. It is a group of sellers under one listing, so when you see "5 new 4 used", it means that 9 sellers are offering that product and competing for your business.
One buyer could have got theirs in perfect packaging on a next day tracked service while the other could have got it a week later by royal mail on an untracked 2nd class service. The Amazon buyer often thinks they are reviewing one seller, but they are not.
Chances are your reviews came from different sellers, but if not, I would read further into their shop feedback to see if the seller is duff or the reviewer is harsh.