>Perhaps unsurprisingly, a couple of extremely positive reviews by current employees have suddenly cropped up for that company as well. So positive they feel a bit like HR plants.
Most of the responses here are spot on but I want to address that one specific point. It's highly unlikely those new reviews are HR plants. Instead, the company is clearly aware of the negative review and the fact that it's getting publicity and has asked/encouraged their current staff to post their own reviews.