Its good to see positive reviews, because it is human nature to shout about poor service, but when things go right in most cases it is what we want (and should expect) so we are not inclined to make a song and dance about it.
As customers expectations become greater, it is increasing hard for any business or organisation to make an exceptionally good impression, so when a customer feels their expectations have been exceeded to the point where they want to tell others about it, it represents a real achievement.
Even when a product fails, and causes annoyance, the situation can often be retrieved if the follow up action is exceptional. There is a motor mover manufacture who has an enviable reputation because of their second to none customer service.
The only people who are hurt by good praise, are the competition, and unless they want to fail, they should realise the way forward is to strive for excellence, so they can also generate real praise and new customers.