I'm not sure any rating should be made with others in mind. It is YOUR rating. However, if you describe the services in detail, which you thankfully have, other members will make their own mind up. Your rating of +ve, n or -ve is subjective and may lead to conversations, but ultimately the description is everything. Again, thank you for the detailed review
I fully agree - it's your description/rating.
I think price is also important. Even if the service, place, or whatever is not excellent, but the price is low, I would still say it is Positive because you cannot expect a Ferrari for the price of a Corsa. On the contrary, I would consider getting a top of the range Audi for the price of a Ferrari a Negative.