Lower ratings most of the times are honest reviews and if seller replies to them you can see how much they care about the customer and if they are being honest business
If the seller/owner responds to a negative review, this is a red flag for me. Indicates a sort of hypersensitive, pressuring attitude. I empathize that they might wanna "tell their side" but in the end it betrays a clingy monitoring of Your Image that makes me as a potential customer feel like I may be walking into a spiderweb.